I found this blurb on Cbs.sportsline.com:
Shortstop Bobby Crosby is not expected to miss significant time for the Oakland Athletics with a strained right triceps muscle, an injury he sustained in batting practice Friday before the A's played the Los Angeles Angels. Crosby was examined Saturday by team orthopedist Jerrald Goldman, who was pleased with Crosby's improvement and didn't think the 2004 AL Rookie of the Year would need to spend time on the disabled list. "It's certainly not a DL type of thing," Goldman said. "It's days rather than weeks." Crosby's injury is deep beneath the armpit where the triceps muscle begins - an uncommon spot that makes it difficult to treat.
It also said that he is definitely out for the rest of the A's series against the Angels. Other than that, it looks like he falls into the dreaded "day to day" category...
"I have great faith in fools; self-confidence my friends call it." ~Edgar Allen Poe