Mejia was claimed off waivers by the Angels and added to the team's big-league roster Saturday.
After being primarily a starter for most of his professional career, Mejia had pitched exclusively out of the pen in 15.1 innings for the Twins this season. The change of roles has not treated him well, as he owns an awful 8.80 ERA and a 16.9 percent strikeout rate. It's not yet known whether the Angels will leave in him in the bullpen or transition him back to a starting role.