DENVER -- Rockies right-hander Ubaldo Jimenez's strained left hamstring responded well to a bullpen session on Thursday, but manager Jim Tracy will delay his next start. The move was part precaution, part honor.
Instead of starting Saturday against the Padres at PETCO Park, he'll start Tuesday in the second of three games against the Giants at AT&T Park. The Rockies lead the Giants by 4 1/2 games in the National League Wild Card standings.
Right-hander Esmil Rogers, 24, who went a combined 11-7 with a 4.41 ERA at Double-A Tulsa and Triple-A Colorado Springs, will be activated to make his Major League debut. Rogers entered the system as a shortstop and hit .209 from 2003-05 before switching to the mound in '06. He quickly became one of the system's top prospects.
Looking further ahead, Jimenez (13-10, 3.32 ERA), who has gone 10-4 with a 2.85 ERA since June and has emerged as one of baseball's top young pitchers, is in line to start on Oct. 2 -- the opener of the season-ending three-game road set against the NL West-leading Dodgers. The Rockies trail the Dodgers by two games, so that series potentially could carry extreme meaning.
"I wasn't pitching against them [originally]," Jimenez said. "I feel bad that I'm not pitching on Saturday, but I do get a big game at the end."
Jimenez pitched six innings and gave up three runs on six hits for a no-decision in Monday's 4-3 win against the Reds. He pulled up after scoring on Todd Helton's single in the third inning but did not leave the game for another three innings.
Asked what changes he'll make in the future, Jimenez said, "Run like a pitcher."
Tracy said he simply did not want to risk losing Jimenez for the season on a "quick-twitch" play such as a fielding play.
"Could he pitch on Saturday? Yeah, he could," Tracy said. "Would we be taking a little bit of a chance? Yes, I think so."
The Rockies already have two other injury questions in their rotation. Aaron Cook (10-6, 4.47 ERA) hasn't pitched since suffering right shoulder soreness on Aug. 21, although he is throwing a bullpen session on Friday and hopes to return shortly thereafter. Righty Jose Contreras (1-0, 1.86) suffered a right quadriceps strain during Thursday's 5-1 victory over the Reds.
Rogers went 8-2 with a 2.48 ERA in 15 starts at Tulsa, and 3-5 with a 7.42 ERA in 12 games, including 11 starts, at Colorado Springs.
Thomas Harding is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.