The Giants reinstated Mahle (hamstring) from the 15-day injured list to start Wednesday's game against the Athletics.
Mahle, who made his last start May 26, will start Wednesday in his return from the IL. Before being shelved with a left hamstring strain, the 31-year-old posted a 6.04 ERA, 1.54 WHIP and 57:24 K:BB in 56.2 innings. Tristan Beck was optioned to Sacramento to make room for Mahle on the roster.