Perdomo is listed as the Giants' probable starting pitcher for Sunday's game against the Mets.
The left-hander received his first promotion to the big leagues Tuesday when rosters expanded to 28 players and made his debut later that day in Pittsburgh, allowing one run on three hits and one walk with four strikeouts over four relief innings. Perdomo, who posted a 5.10 ERA, 1.59 WHIP and 36:20 K:BB across 47.2 frames in nine starts for Triple-A Sacramento, will now get a look in the major-league rotation, though it may end up being just a spot start.