I want to preface this by saying that I am not a statistician. This could all be hogwash, so bear with me.
Last year, Joe Blanton reach career bests in a few categories, including strikeouts (140) and K/9 (5.48). While Blanton is pitching deep into games this year (sample size warning), he is not striking out many batters. Blanton's 3.56 K/9 is by far the lowest of any of the A's starters, and good for 45th out of the 48 pitchers who have amassed at least 40 innings this year.
In addition to his low strikeout totals, Blanton is giving up 10.5 H/9, as opposed to last year's rate of 9.39. While his BB/9 is as solid as it’s ever been, his WHIP has jumped to 1.347 (last year: 1.217). His ERA+ is 99, even though he’s seemingly having a good season. It’s not a huge sample, but on average, Joe’s struggles typically seem to escalate after the fifth inning.
That Joe struggles later in the game isn’t any huge revelation. Conventional wisdom says that batters get more comfortable after having seen a pitcher a couple times already. On top of that, pitchers tire and lose effectiveness as a game goes on. With decreased command, pitchers will typically either walk more batters or leave pitches in the zone for hitters to demolish. The graph isn’t perfect, because with such a small sample, one bad inning can skew all the rest of the data.
So, is Bob Geren leaving Blanton in too long? While Blanton has given up 15 runs (12 earned) in the 40 first-through-fifth innings that he’s pitched, he has been tagged for 12 runs (all earned) in the 15 2/3 innings that he’s pitched beyond the fifth. Blanton’s blanked the opponents in four seventh innings so far and given up two runs and one run, respectively, in the other seventh innings he’s pitched in. He’s had one shutout eighth inning and given up runs in both of the other eighth innings he’s pitched in. While he’s pitched six shutout sixth innings, he’s allowed a lot of people to reach base.
Joe gives up a lot of hits, and almost always has baserunners to deal with. It’s hard for me to make any conclusions with this data, other than the obvious ones. Perhaps you guys have some insights.
Let’s go back to the subject of strikeouts. With only eight starts in the books, it’s probably a bit premature to try to find the reason why Joe isn’t striking anybody out. Is it his stuff?
I found an article at THT from February that tries to find the best pitch in the majors in 2007. It’s an interesting study, though I’m not sure if it accounts for park effects. According to the study, Joe Blanton had the second-best slider in the majors last year. His changeup was also rated second in the majors, while his sweeping curveball was ranked 15th.
Most pitchers with good offspeed stuff still throw fastballs the majority of the time to keep hitters off-balance. Blanton is no different. He threw his fastball 54.2% of the time last year, and is only slightly below that amount in 2008 (53.5%). His changeups have been slightly more frequent this year than in the past, moving from 15.1 to 16.9. So early in the season, it’s fair to say that this could be random variation. His curveball selection has risen from 14.4% to 20.9%.
Last year, Joe Blanton threw his slider 16.3% of the time (567 times out of 3481 total pitches). This year, he has only thrown it 8.7% of the time. In essence, he has thrown the curveball in place of the slider almost half the time. Why has he been so stingy with the sliders? Could the lack of second-best-in-the-league sliders have anything to do with his dangerous decline in strikeouts?