Colorado left-hander Tyler Anderson (5-3, 4.23 ERA) will oppose Suarez (3-4, 4.18).
Before his team lost 8-1 on Tuesday to the Rockies, Giants manager Bruce Bochy announced that Johnny Cueto will be reinstated from the 60-day disabled list to start Thursday against St. Louis and Jeff Samardzija will come off the 10-day disabled list and start Saturday against the Cardinals.
Cueto (elbow strain) went 3-0 with an 0.84 ERA in five starts for the Giants this season. His last start for the Giants came April 28, and he pitched 7 2/3 scoreless innings in two rehab starts for Triple-A Sacramento.
"Johnny's set to go," Bochy said. "He passed all the tests, checked every box off. Been throwing the ball well. Hasn't given up a run there. Bullpen [session Monday] went fine. Been hitting, bunting. I talked to Johnny. He said, 'I'm ready to go. I feel better now than before [the injury].' When you get one of your big guys ready to go, you pitch him."
Bochy said Cueto would be limited to 85 pitches Thursday, and Derek Holland, if he doesn't come out of the bullpen in the Rockies series, would back up Cueto.
Samardzija will pitch for the Giants for the first time since May 29. Bochy said that Dereck Rodriguez, who was scheduled to pitch Thursday, will instead start Friday. Madison Bumgarner, of course, will take his regular turn Sunday. That leaves Suarez or Chris Stratton for the final spot in the rotation. Both pitchers have minor league options.
Suarez might have the advantage because he has pitched well lately. He went 2-0 in six June starts, and in his last outing Friday at Arizona, he allowed one run in six innings. Suarez made his Coors Field debut and first start against the Rockies on May 28 and allowed four runs (three earned) in five innings in a no-decision after heeding advice from catcher Buster Posey.
Suarez said, "I remember the last time we were, before my bullpen, Buster came up to me and he was like 'As long as you keep throwing it right, it'll be fine. But if you try too much, that's the problem you'll have. Your stuff isn't as good.' I just made sure to just throw it normal."
Meanwhile, Stratton gave up a career-high 11 hits and a career-high eight runs in 5 2/3 innings Tuesday. In his past six starts, Stratton is 1-3 with a 5.79 ERA.
Anderson threw a career-high eight scoreless innings with one walk and eight strikeouts Wednesday at Los Angeles in a 3-1 win over the Dodgers. Anderson is 2-2 with a 2.70 ERA in his past five starts with six walks and 32 strikeouts in 33 1/3 innings. He's 0-2 with a 5.56 ERA in four career starts against the Giants, including a no-decision May 20 at AT&T Park where he gave up five runs in 5 1/3 innings as the Rockies lost 9-5.
The Rockies have won 14 of their past 16 games from the Giants (45-42) at Coors Field. The Rockies (43-43) have climbed back to .500 by winning five of their past six games. They have been getting outstanding starting pitching, the latest effort being seven scoreless innings Tuesday from Antonio Senzatela in his first start this season for the Rockies.
The Colorado starters have pitched well in six of the past eight games, going 4-0 with a 2.15 ERA in that stretch and allowing 12 earned runs and 31 hits in 50 1/3 innings with 11 walks and 41 strikeouts.
"We're only going to go as far as they do," Rockies third baseman Nolan Arenado said. "They're pitching great. They're giving the offense a chance. Quick innings, which is huge."