In a corresponding move, 30-year-old right-hander Taylor Cole was designated for assignment.
Buchter, 33, signed a minor-league deal with the Angels prior to camp opening. In five spring appearances, the lefty allowed zero runs on three hits while striking out five.
Buchter spent the previous two seasons with the division-rival Oakland Athletics. Over 84 2/3 innings, he posted a 2.87 ERA and 4.30 FIP.
While effective, the minimum three batter rule - set to be implemented when the 2020 season gets underway - seemed to jeopardize Buchter's future. Last year, Buchter faced two or fewer batters in 23 of 64 appearances.
Cole has spent the previous two seasons with the Angels, owning a 4.62 ERA and 3.31 FIP in 87 2/3 innings over that span.