Mr. E made an observation on Jeff Karstens on a thread earlier (that Hurdle was cautious with him after the 4th inning after being inserted into the starting rotation), which got me started looking a lot at Jeff Karstens last year broken up month-by-month.
*Fangraphs and BBRef differed slightly in some places I looked, namely in BABIP. Anytime there was a conflict, I went with BBRef.
Jeff Karstens 2011 season: 9-9, 3.38 ERA, 1.207 WHIP, 161.2 IP, 113 ERA+, 5.3 K/9, 1.8 BB/9, .721 OPS against, .278 BABIP bWAR = 3.0
His first 3 appearances of the year, as well as an extra-inning game in May, were relief gigs. We'll take the 7.2 IP he totaled out of the bullpen and subract them from 161.2 for 154 IP in his 26 starts. That's good for 5.923 IP/start in 2011 for Karstens. I'll leave his relief appearances in for rate stats (mainly because I'm lazy).
April: 2-1, 3.57 ERA, 1.368 WHIP, 5.667 IP/start, 7.1 K/9, 2.8 BB/9, .762 OPS against, .318 BABIP
Karstens struck out 5 of the 14 batters he faced (weirdly walking 3) in his 3rd relief appearance. His K/9 and BB/9 are both higher than his season averages because of this. He got shelled (5 ER, 8 H in 4.1 IP) in his first start. He still walked just one guy in each of his 3 starts, which sets the pace for his success in 2011.
May: 1-2, 3.58 ERA, 1.229 WHIP, 5.133 IP/start, 7.2 K/9, 1.3 BB/9, .834 OPS against, .288 BABIP
Karstens has started not walking anybody. His K/9 are still high. He gave up 7 homeruns this month (his highest total for any month) and his OPS against reflects that.
June: 3-0, 1.52 ERA, .823 WHIP, 6.889 IP/start, 3.3 K/9, 1.5 BB/9, .579 OPS against, .169 BABIP
Here was the fun month to watch. Karstens went exactly 7 innings in 4 of his 6 starts and 6.2 in the other two (mad consistency). He gave up 6 homeruns, but 3 of them were in one game against Boston (on my birthday). The 3 HR and 3 BB he gave up in this game are both season highs (he matched 3 BB in a relief appearance in April as well as a start in July). He still won that game and was just on fire all month long. That BABIP is crazy lucky (and contributed to that .579 OPS against) and he compounded that with not walking guys to put together a very good month. This is ironically (or tellingly) his worst K rate as well.
July: 2-1, 2.06 ERA, 1.086 WHIP, 7.000 IP/start, 3.6 K/9, 1.5 BB/9, .604 OPS against, .265 BABIP
The traditional numbers were better in June, but I think July was his best month as a pitcher. He walked 3 again (giving up 3 runs) in Atlanta. but also tossed a complete game shutout in Houston (using just 83 pitches when they still had Hunter Pence and Michael Bourn). This was also Pittsburgh's crest of the season; they were 48-43 after that Houston game and in 1st place in the NL Central. The K's are low again, but I'm impressed that his BABIP has come back to Earth without his OPS against swelling linearly (about 100 points higher BABIP, OPS against up only 35).
August: 1-3, 7.46 ERA, 1.737 WHIP, 5.067 IP/start, 7.8 K/9, 2.1 BB/9, .892 OPS against, .402 BABIP
Everything comes crashing down for both Karstens and the Pirates. Karstens had his worst outing against San Diego (the only game I got to go to PNC for this year) during the Bucs' 8-game losing streak that took them out of contention. Karstens only walked 6 batters all month, but his rates are high because he just didn't make it very deep in games this month (less than 4 IP in 2 of his 5 starts). This is, however, his highest K rate of the year (interesting again). All of that luck in the BABIP and OPS that he'd experienced came back to the mean.
September: 0-1, 4.35 ERA, 1.425 WHIP, 5.167 IP/start, 4.4 K/9, 2.6 BB/9, .745 OPS against, .297 BABIP
Only 2 starts in September: one against St. Louis as they were streaking into the playoffs and the other a 1-0 pitchers' duel loss to Arizona where MVP 3rd runner-up Justin Upton hit a solo shot off of Karstens in the 6th. This sample size is too small to really infer anything; even in the view of month-by-month, 2 games is just not enough data.
Jeff Karstens had a very solid 2011. His success stems from nearly elimnating walks: he walked 29 total batters in his starts all season, 6 of those being intentional (all to lefties). Increases in his K rate corresponding with decreases in overall performance suggest that his role is as a pitch-to-contact pitcher; crucial as his fastball averaged only 88.9 MPH last year... the additions of Barmes and Barajas should help him. Over the past 3 years, he's increased his GB rate by 7.7% (38.5%-46.2%) while decreasing his FB rate by 9% (45.5%-36.5%). Curiously, 14 of 16 would-be basestealers succeeded against Karstens in 2011; I have no idea how much of that is his fault.
As I was looking at all of these numbers, I was curious as to whether or not Karstens got lucky with his matchups. I do not think this is the case. He beat Houston twice to begin July, but this was when they still had a MLB lineup with Pence and Bourn; he drew Cincy followed by @Atlanta and @Philly the rest of that month. For every time he beats up on the Disastros or Tribe, he has a matchup against St. Louis or Milwaukee or Boston. Somehow, he only got one start against the Scrubs: a day game in late May at Wrigly (though he did get a win in relief against them in his first appearance of the year).
I believe that this level of performance is sustainable. Improvements in GB/FB rate is likely and that consistent level of control is impressive. Karstens' 2011 reminds me of a poor man's version of Cliff Lee's 2008 where he just stopped walking people. I'm not crazy enough to project Karstens to become Cliff Lee, but 2008 was Lee's age 29 season while 2011 was Karstens age 28 season. Karstens will have to seriously cut down on the homeruns, but he's certainly on his way with the BB rate. Hey, if Morton's Operation: Roy Hallady comes around and Karstens becomes Cliff Lee 2.0, that's an incredibly cheap and effective top of the rotation and Ray Searage deserves a medal or Nobel Prize or something.