For starters, his walks/9 are up (from 2.4 to 3.6) and strikeouts/9 are down (from 7.1 to 5.3) relative to last year (which was representative of the previous couple of years). I don't know how to explain that; but here's something that may partially explain his struggles: bad luck. This year, opposing batters are hitting .296 off Lackey, well above 2009's .263 (or his career average of .265). Perhaps not coincidentally, Lackey's BABIP (the percentage of balls put into play that turn into hits) is .330. Does this mean the Sox defense is letting Lackey down by failing to turn batted balls into outs? Well, no -- the league average BABIP this year is .295 (which is roughly what it is every year). By contrast, the BABIP for all hitters facing the Sox this year is .290, meaning the Sox have, for reasons of luck or skill, been slightly more efficient at turning batted balls into outs than the rest of the league. So it's probably not the defense behind him that's causing Lackey's troubles. Indeed, in general, BABIP simply does not vary that much -- with larger sample sizes, it always regresses towards .300 (although it is certainly possible to have such a high BABIP over an entire season, as Lackey did in 2005).
So is it just luck? Probably not -- first, if Lackey's location is poor, as is suggested by his increased walks and decreased strikeouts, perhaps he's leaving more pitches over the plate, leading to hard contact. Second, a high BABIP by itself could not explain all of Lackey's results this season: obviously, it can't explain the walks and strikeouts, but it also can't fully account for the average and slugging percentage of opposing hitters, either: for comparison, in 2005, Lackey's BABIP was .327, just 2 points shy of his current .329. Even so, that year, opposing batters hit only.258/.325/.362 against him.
So what's the upshot here? Lackey's luck may well even out a bit, and his BABIP may go down as the year goes along. Even so, there's no reason to think that hitters won't keep squaring up his pitches until he can start spotting them better.
