The Angels optioned Plesac to Triple-A Salt Lake on Saturday.
Plesac has struggled in three starts with the Angels this season, giving up 11 runs in 12 innings while striking out five batters and walking seven. He'll return to Salt Lake in an effort to get back on track, but he hasn't been much better in the minors with a 5.42 ERA through 13 starts with the Bees. Andrew Wantz will come up from Triple-A to fill the vacancy in Los Angeles' pitching staff.