The Angels recalled Klassen from Triple-A Salt Lake on Friday.
Klassen is making the start Friday against the Marlins. He opened the season in the Halos' rotation but was hammered for seven runs (six earned) on seven hits and 10 walks with six strikeouts across 4.2 innings spanning two starts before he was dispatched to Salt Lake. The 24-year-old right-hander pitched to a 3.96 ERA, 1.42 WHIP and 88:46 K:BB across 19 starts at Triple-A.