Jason Hammel is going back to the big leagues. The Rays just announced his promotion and that Jae Seo has been outrighted to Durham. The second open spot in Tampa Bay's staff will be filled Tuesday.
I would think Hammel's return signals that Edwin Jackson is headed to the bullpen.
Hammel has always been a starter and Jackson has done both. Plus, Jackson is 0-7 with a 7.39 ERA this season in 11 starts with the Rays. Of course, Hammel was 0-6 with a 7.77 ERA last year in nine major-league starts.
UPDATE: The Rays are also close to signing former A's reliever Jay Witasick, according to the St. Petersburg Times, and will make room on the 40-man by designating Tim Corcoran for assignment.
If Corcoran clears waivers, that could start the ball rolling, sending Richard De Los Santos back to Montgomery (his promotion wasn't expected to be a long-term move anyway) and someone leaving the Biscuits.