Only if he goes unclaimed on waivers. If another team picks him up, that club would inherit the obligation to keep Almanzar on their active roster for the balance of the season. If not, he'd be offered back to Boston. If the Sox want him, they'd have to pay the Orioles $25,000 -- half the $50,000 drafting fee the O's forked over when they selected him in the Rule 5 draft in December. If the Sox decline, Baltimore can outright reassign Almanzar to a minor league affiliate.
Considering Boston paid $1.5M to sign the kid, I doubt they'd bat an eyelash at spending another $25k to get him back. He's still just 23. Of course, he'd once again be eligible for the Rule 5 this winter, and I can't see the Sox expending a 40-man spot on him unless he completely sets the world afire over the next couple of months.