Devine, who was slowed earlier this month because of bicep tightness, struggled with his command and mechanics at times this spring. He missed the last two seasons because of Tommy John surgery.
Devine was charged with three runs in 4 1/3 Cactus League innings this spring.
"Obviously, we'll go with other relievers to start the season. But I'm encouraged with his last two outings, and he feels positive with where he is at, right now, physically," manager Bob Geren said. "It's not usually encouraging when you send somebody down, but in this particular case, we are very happy. He's healthy, good velocity. He feels like the Minor Leagues is exactly what he needs."
2010 Spring Training - null
Sights & Sounds
Spring Training Info
With the move, the A's have 33 players remaining in camp, which includes 30 players on the 40-man roster and three non-roster invitees.