Mejia (calf) will begin a rehab assignment with High-A Fort Myers on Monday, Brandon Warne of ZoneCoverage.com reports.
Mejia has been out since the beginning of May with a strained right calf. He recorded an ugly 8.74 ERA in 11.1 innings of relief work before hitting the injured list. After missing nearly six weeks, it's likely that he'll need at least a handful of rehab appearances before returning to the big leagues. It's possible he isn't given a major-league roster spot once healthy, but he's out of options, so the Twins are likely to give him a chance to work through his early struggles.