Mejia was designated for assignment Saturday, Shannon Drayer of 710 ESPN Seattle reports.
The Twins needed to make room for Jake Odorizzi (blister) to be activated from the injured list. Once a top prospect, Mejia was no longer being developed as a starting pitcher, and he struggled as a big-league reliever. He could get claimed by another team, given his pedigree and the fact that he's left-handed.