Thursday, November 06, 2008
Twins 2008 Minor League Numbers: Pitchers
Monday's entry discussed the importance of putting minor-league performances into proper context based on adjustments for leagues, run-scoring environments, defensive positions, and ages. It also laid out my method for arriving at those context-adjusted numbers, so you'll want to read that before going any further with today's entry. After using those adjustments Tuesday to examine how the Twins' hitting prospects fared in 2008, it's now time to cover the team's pitching prospects.
Evaluating pitchers is typically more difficult than evaluating hitters, because pitchers rely heavily on the defense behind them. Beyond that, pitchers often exit games with runners on base and whether or not those runners score off the pitcher who comes in from the bullpen can have a big impact on ERAs and win-loss records. All of which is why, rather than looking at more traditional stats, my focus is instead on a metric called Fielding Independent Pitching (FIP).
Designed to look just like ERA--the MLB average was right around 4.35 this year--FIP measures only things that a pitcher is individually responsible for, including strikeouts, walks, and homers. The idea is to remove the impact of the defense behind them, the pitchers who relieve them, and any luck involved. After calculating FIPs for each of the Twins' minor-league pitchers, the next step is to adjust the totals based on the system's various run-scoring environments.
From Rochester and New Britain to Fort Myers and Beloit, the Twins' minor-league system is filled with low run-scoring environments. That makes hitting prospects look worse and pitching prospects look better, and in both cases the end result is misleading raw numbers. However, accounting for that and normalizing the run-scoring environments to fit the level of offense in MLB paints a far clearer picture. Basically, the adjustments put everyone on an even playing field before evaluating their performance.
Tons of pitchers in the Twins' minor-league system post ERAs in the 3.00s and 4.00s every year, but many of them do so while being below average at preventing runs because their league was such a low-scoring environment. MLB as a whole had a 4.32 ERA in 2008, while the four full-season leagues in the Twins' system averaged a 3.95 ERA. You're bound to post pretty ERAs when offensive levels are 10 percent below MLB, which is why run-scoring adjustments are important.
Before getting to the good stuff, please note that these are not my rankings of the Twins' top prospects. That annual list will be published later this offseason and includes both multi-year track records and long-term potential as huge factors, whereas the numbers below focus solely on what each player did this year. The point here is to simply determine who had the best 2008 season by putting everyone's numbers through the same context-adjusting system. Here are the adjusted FIPs:
100+ INNINGS FIP 70-99 INNINGS FIP 40-69 INNINGS FIPIt's great to see Francisco Liriano atop the list of best FIPs from pitchers with 100-plus innings and his 3.26 adjusted FIP at Triple-A jives with the 3.87 FIP he had in Minnesota. Even if he were just another 24-year-old prospect with those numbers, Twins fans would have every right to be excited about his long-term potential. Of course, prior to Tommy John surgery Liriano had a 2.44 FIP between Double-A and Triple-A in 2005 and a 2.55 FIP for the Twins in 2006, so he's still a long way from that dominance.
Deolis Guerra is sadly at the other end of the performance spectrum, ranking dead last in adjusted FIP among pitchers with 100-plus innings. Acquired from the Mets last winter as the co-centerpiece of the Johan Santana trade, Guerra spent the year at high Single-A despite being a teenager and had a 5.47 ERA with a 71-to-71 strikeout-to-walk ratio in 130 innings. He won't be 20 until April and wouldn't have been at high Single-A if the Mets hadn't misguidedly rushed him before the deal, but 2008 wasn't pretty.
As a reliever in the low minors Robert Delaney failed to crack my Top 40 Twins Prospects list for 2008 despite posting the second-best adjusted FIP in the system last year, but back-to-back seasons with a sub-2.40 FIP makes it safe to say that he's for real. Delaney was undrafted out of college, but saved 18 games with a 1.23 ERA and 72-to-11 strikeout-to-walk ratio in 66 innings this year--including thriving at Double-A as a 23-year-old--and has a 1.91 ERA and 185-to-28 strikeout-to-walk ratio for his career.
Amazingly, Delaney didn't even have the best adjusted FIP among Twins relief prospects this season. In fact, it wasn't close. Anthony Slama posted one of the most ridiculous pitching lines you'll ever see with a 1.01 ERA, 110-to-24 strikeout-to-walk ratio, zero homers allowed, and a .173 opponent's batting average in 71 innings at high Single-A. Equally amazing is that despite Slama being 24 years old and absolutely overpowering Florida State League hitters, the Twins inexplicably refused to promote him.
Instead of seeing what he could do at Double-A against players his own age, Slama was left to rack up absurdly good numbers by dominating younger competition. Slama's season was incredible no matter how you look at it, but pitching against prospects 2-3 years his junior certainly takes some of the air out of his performance. As for how much, that's where adding to adjustments for run-scoring environments by factoring in both age and level of competition comes into play:
AGE LEVEL FIP%As you can see, even adjusting for run-scoring environment, level of competition, and age doesn't keep Slama from having by far the best season of any pitcher in the Twins' system. Docking him for being a 24-year-old at Single-A deflates his performance quite a bit, but there's only so much wind that can be taken out of the sails of a guy who faces 280 batters and strikes out 40 percent of them without giving up a homer. Liriano was very good and Delaney was great, but Slama was absolutely extraordinary.
After making the various adjustments, the Twins had a total of 30 pitchers who were above average in 2008, whereas 25 position players were above par. In terms of performances from MLB-ready pitchers, Liriano was 34 percent above average and will obviously be in the Twins' rotation next season. Bobby Korecky was 22 percent above par and at 28 years old has been deserving of a spot in the bullpen for a while now, while Mariano Gomez and Ricky Barrett also pitched well enough to be relief options.
Kevin Mulvey joined everyone else in the Santana package by having a disappointing season, but after adjusting for context his performance was actually slightly above average for a 23-year-old starter at Triple-A. Unfortunately, the same can't be said for Philip Humber, who despite being two years older than Mulvey turned in the ninth-worst context-adjusted numbers of any pitcher in the Twins' system who logged 40-plus innings. Mulvey was disappointingly mediocre, but Humber was just plain awful.
Tyler Robertson ranked No. 3 on my list of the Twins' best prospects coming into the season and was 32 percent above par as a 20-year-old at high Single-A before being shut down in July with shoulder problems. Jeff Manship and Mike McCardell added to their strong track records and continue to look like potential mid-rotation starters, while David Bromberg emerged as one of the Twins' top prospects in his first season above rookie-ball by rating 29 percent above average at low Single-A.
First-round pick Shooter Hunt had a strong pro debut, but seventh-round pick Daniel Osterbrock and third-round pick Bobby Lanigan made even better first impressions. As a 21-year-old with lots of major college experience Osterbrock was a man among boys at rookie-level Elizabethton, but even factoring in his age a 104-to-8 strikeout-to-walk ratio in 75 innings stands out 60 percent above average. Based on the very early results, the 2008 draft has been a success for both pitchers and hitters.
Once you're done here, check out my latest "Daily Dose" column over at Rotoworld.
Tuesday, November 04, 2008
Twins 2008 Minor League Numbers: Hitters
Yesterday's entry discussed the importance of putting minor-league performances into proper context based on adjustments for leagues, run-scoring environments, defensive positions, and ages. It also laid out my method for arriving at those context-adjusted numbers, so you'll want to read that before going any further with today's entry, which reveals what putting the 2008 numbers into context shows about the Twins' position-player prospects. Later this week I'll do the same for pitching prospects.
Before getting to the good stuff, please note that these are not my rankings of the Twins' top prospects. That annual list will be published later this offseason and includes both multi-year track records and long-term potential as huge factors, whereas the numbers below focus solely on what each player did this year. The point here is to simply determine who had the best 2008 season by putting everyone's numbers through the same context-adjusting system.
The first step is taking raw numbers and adjusting them for run-scoring environments, with the idea being that everyone should first be placed on an even playing field before evaluating their performance. For example, catching prospect Wilson Ramos hit .288/.346/.434 in 126 games for Fort Myers at high Single-A, which looks relatively mediocre at first glance. However, the Florida State League as a whole batted just .256/.329/.376 while scoring 8.5 combined runs per game in 2008.
The run-scoring environment that Ramos played in this year was almost 10 percent worse for offense than MLB, which is a major part of his unspectacular numbers. Once you normalize the Florida State League to fit the level of offense found in MLB, then Ramos' hitting line improves to .297/.350/.480, which is extremely impressive from a 20-year-old catcher (the average MLB catcher hit .257/.325/.390 in 2008) and does a far better job of showing his outstanding potential than the raw numbers.
Because the Twins' minor-league system is filled with teams playing in low run-scoring environments, normalizing the organization-wide hitting numbers causes most position players to get a Ramos-like boost. Putting hitting prospects in leagues where the average team doesn't even slug .400 will do a lot to skew the perception of their ability and that's the case throughout the Twins' system. Here are the top adjusted 2008 hitting lines from Twins minor leaguers with 200-plus trips to the plate:
PA AVG OBP SLG OPSBen Revere got most of the attention by flirting with .400 for much of the year, but on a per-game basis Angel Morales was actually the Twins' best minor-league hitter this season. Despite being 18 months younger than Revere and six months younger than 2008 first-round pick Aaron Hicks, Morales batted .301/.413/.623 in 54 games at short-season Elizabethton, leading the rookie-level Appalachian League in homers and slugging percentage.
Morales' numbers are plenty great on their own, but become even better after accounting for the fact that the Appalachian League as a whole hit .262/.331/.387. Slugging .623 in an environment where the average slugging percentage was a measly .387 is equivalent to slugging .670 in an environment with MLB-level offense. Morales' breakout consists of just 218 plate appearances, so there are sample-size issues at play, but an 18-year-old posting an adjusted hitting line of .303/.415/.670 is pretty sick.
Of course, Revere wasn't bad himself. He came up short of the .400 mark by hitting "only" .379, but after accounting for the pitcher-friendly Midwest League his adjusted batting average jumps to .397. Morales and Revere were the only hitters in the system to post an adjusted OPS above 1.000 and Hicks ranked fourth at .985, which is amazing from a trio of center fielders selected out of high school in the past two drafts. Here are the top adjusted Isolated Power and Isolated Discipline marks:
IsoP IsoDBased solely on his .239 batting average you'd conclude that 2006 first-round pick Chris Parmelee had a horrible season, but that's far from the case. Parmelee hitting just .239 this season and .246 for his minor-league career certainly isn't a good thing and raises big questions about his long-term potential, but focusing strictly on that overlooks great power and plate discipline. Only Morales and Evan Bigley displayed more raw power than Parmelee, and no one in the Twins' system had more patience.
Despite batting just .239, Parmelee posted an adjusted .250/.398/.556 line that ranks as the sixth-best production from any hitter in the Twins' system. To put Parmelee's power in perspective, consider that he played alongside Revere at Beloit and they posted slugging percentages within one point of each other (.497 versus .496) despite a 140-point gap in the batting average (.379 versus .239). Unlike most guys in the system Parmelee has the secondary skills to make a big impact without a big average.
All of the above numbers have been adjusted for run-scoring environments, but further adjustments for ages and defensive positions are also important. For example, Garrett Jones' adjusted .280/.339/.498 line looks pretty good and ranked as the 15th-best among the system's hitters, but his .837 adjusted OPS ceases looking so great given that he was a 27-year-old first baseman playing his fourth straight season at Triple-A. In fact, for a 27-year-old first baseman at Triple-A that's far from impressive.
Meanwhile, Ramos and Jones essentially had identical adjusted hitting lines, but an .830 OPS from a 20-year-old catcher facing older competition at high Single-A is vastly more impressive than an .837 OPS from a 27-year-old first baseman facing younger competition during his fourth crack at Triple-A. Ramos' season suggests that he has the potential to develop into a good-hitting everyday catcher in the majors. Jones' season suggests that he has the potential to spend another few years at Triple-A.
Attempting to compare players like Ramos to players like Jones shows the importance of the next step, which is making further adjustments for age and defensive position. In other words, how does each player's offense compare to other players at his position, and how old was each player relative to the level he was at and prospects he was playing against. If you take the normalized numbers above and apply further adjustments based on age and position, you get the following:
AGE LEVEL POS OPS%After factoring in leagues, run-scoring environments, defensive positions, and age, the Twins' system had 25 players who were above-average offensively in 2008. Morales led the way at 60 percent above average, followed by Revere at 41 percent and Hicks at 38 percent. Ramos led the non-center fielders at 27 percent above par (whereas Jones doesn't even crack the list) and Parmelee's mostly overlooked season rounds out the top five at 23 percent better than average.
Among players who've advanced past Single-A, Luke Hughes led the way at 21 percent above average, followed by Steven Tolleson at 15 percent and Danny Valencia at 14 percent. That trio represents the closest thing the Twins have to good, MLB-ready hitting prospects and they were joined in the top 10 by rookie-ball standouts Bigley and Jonathan Waltenbury at 19 percent above average. Incidentally, with enough plate appearances to qualify Denard Span would have ranked fifth at 24 percent above par.
Once you're done here, check out my latest "Daily Dose" column over at Rotoworld.
Monday, November 03, 2008
Twins 2008 Minor League Numbers: Intro
Later this offseason I'll be putting together my annual "Top 40 Twins Prospects" rankings for 2009, but before that happens it's important to evaluate how the team's minor leaguers performed in 2008. When it comes to major-league players most people recognize the need to take things like defense, home ballpark, league, and run-scoring environment into account when evaluating their performance, but for some reason those same factors are often overlooked in examining minor-league players.
Putting players' performances in context is even more important in the minors, because the differences between ballparks, leagues, and run-scoring environments are often much more extreme than in the majors. For an example, just look at how different the two Triple-A leagues were this year when it came to offense. As a whole, the Pacific Coast League batted .277/.348/.444 and saw 10.5 runs scored per game. Meanwhile, the International League batted .263/.331/.404 and saw 9.0 runs scored per game.
Most people wouldn't think twice about saying that a pitcher "had a 4.00 ERA at Triple-A," but "Triple-A" can be vastly different depending on the league. A 4.00 ERA in the Pacific Coast League was fantastic in 2008, rating about 18 percent better than average. Meanwhile, in the International League that same 4.00 ERA was actually worse than average. In fact, a 4.00 ERA in the PCL was roughly equivalent to a 3.35 ERA in the IL, and that's far from the minors' most extreme league-to-league gap.
Beyond leagues, ballparks, and run-scoring environments, factors like age, defense, and track records are also important. For an example, compare Garrett Jones hitting .279/.337/.484 at Triple-A to Trevor Plouffe hitting .262/.308/.415 split between Double-A and Triple-A. With a 98-point edge in OPS, Jones' season appears on the surface to be much better. However, look deeper and Plouffe likely had the more impressive season and is the superior prospect.
Jones was a first baseman playing his fourth straight season at Triple-A and at 27 years old was 2-3 years older than most of his prospect-aged competition. Plouffe was a shortstop who after beginning the season at Double-A spent the second half playing alongside Jones at Triple-A, where at 22 years old he was 2-3 years younger than most of his prospect-aged competition. Putting their numbers into context casts them in much different lights and the same is true for players throughout the minors.
In an effort to provide an even playing field for evaluating how Twins minor leaguers performed in 2008, I've created a quick-and-dirty system that normalizes all leagues and run-scoring environments to fit the level of offense in MLB this season (.264/.333/.416 with 9.4 combined runs per game). I've also put in adjustments for a player's defensive position and age relative to the level he played at, so that guys like Jones and Plouffe (or, say, Randy Ruiz and Wilson Ramos) can be compared properly.
In recent years it's always been easy to look at the Twins' prospects on an organization-wide level and conclude that they're far stronger in pitching than hitting. While that's been accurate for the most part, it's also important to note that the system features extremely pitcher-friendly run-scoring environments at every level. In other words, good hitting prospects or not it's difficult to collectively post great offensive numbers at Rochester, New Britain, Fort Myers, Beloit, and Elizabethton.
Meanwhile, those same pitcher-friendly run-scoring environments have also played a part in the Twins seemingly always having an abundance of quality pitching prospects. Certainly the organization's focus on drafting and success in developing pitchers are much larger factors, but the system's never-ending stream of pretty ERAs can't be credited entirely to great pitching talent just as the relative lack of huge OPS totals can't be chalked up entirely to a dearth of position-player talent.
Over the next few days my goal will be to put all of that into some context.
Once you're done here, check out my latest "Daily Dose" column over at Rotoworld.