Philadelphia Phillies traded Rich Thompson to Tampa Bay Rays.
Tampa Bay Rays placed RF Brandon Guyer on the 15-Day disabled list retroactive to May 13, 2012. Left shoulder strain.
Tampa Bay Rays transferred RHP Jeff Niemann from the 15-Day disabled list to the 60-Day disabled list.
Colorado Rockies activated OF Eric Young from the bereavement leave list.
Colorado Rockies placed 3B Chris Nelson on the 15-Day disabled list retroactive to May 15, 2012. Left wrist inflammation.
Chicago Cubs recalled LHP Scott Maine from Iowa Cubs.
Chicago Cubs placed RHP Lendy Castillo on the 15-Day disabled list retroactive to May 12, 2012. Left groin strain
Chicago Cubs outrighted Blake DeWitt to Iowa Cubs.
Arizona Diamondbacks outrighted David Winfree to Reno Aces.