Allen Craig, age 29, OPS+ 69 (77 in STL, 28 in BOS)
Plenty of guys have a terrible year once or twice in a (very) productive career. I've been wrong about this often on SoSH. I thought Lowell was cooked (age 31, ops+ of 77). I thought it was crazy to sign Johnny Damon after a bad year in Oakland (ops+ of 83 at age 27). Paul Konerko had one very bad year in Chicago (ops+83 at age 27), and some SoSHers hoped the Sox would pounce. I thought that was a terrible idea. Adrian Beltre had bad, if not awful, years (93 ops+, age 26; 83 ops+, age 30) before coming to the Sox for his late career surge. OTOH--looking at the stats--I thought getting Tony Clark was great--and then he had his awful year, as bad as Craig, actually worse (Age 30, 49 ops+), for the Sox; he is the one example who sort of fell off the table, although he had some OK and even very good years as a part-timer thereafter.
There must be a study of guys who put up a stinker of a year between ages 27-30 and what it means. Of the examples I can think of, it doesn't seem to mean anything much. It could be something wrong that spells a downward spiral (Clark); usually it means a slump before a return to form (all the the others).
I am pretty sure that to have such bad years these guys must all have had very bad stretches in those years when they looked all wrong at the plate.
For a while the SoSH consensus was that Craig must be hurt, and can heal and return to form. Maybe, or maybe we should hope that his injury has healed, but led to bad adjustments and he is just slumping. If that's actually the best case, maybe the fact that he is worse with the Sox than with the Cards is, oddly enough, a good sign: he is clearly really slumping. Slumps suck, but they mostly seem to go away eventually.