Rockies manager Jim Tracy named Ubaldo Jimenez as his starter for Wednesday's 12:37 p.m. MT opener in Philadelphia, but the rest of his rotation is dependent upon the health of De La Rosa.
De La Rosa, who has won a Major League best 16 games since June 1, left Saturday's game against the Dodgers with left groin tightness after throwing a fastball to shortstop Rafael Furcal to lead off the bottom of the fourth.
"He's sore, but we're going to continue to treat him and see if he's able to throw a bullpen [session] on Tuesday," Tracy said. "Obviously, if he's able to do that, then there's a good chance he factors into the mix."
De La Rosa said Saturday he expected to be ready for the playoffs, though he suffered a similar injury last year and felt it for about week.
"We're going to play this out the right way and see where he's at as of Tuesday," Tracy said.
The Rockies' second game against the Phillies is scheduled for Thursday at 12:37 p.m., followed by an off-day on Friday.
That could give De La Rosa a week since injuring the groin before trying to start Game 3 in Colorado on Saturday.
Game 1 starter Jimenez is 15-12 this season with a 3.47 ERA.
"Ubaldo is going to pitch on Wednesday," Tracy said. "Where we go from there, I don't want to step out there any further."
Two other Colorado starters, Jason Marquis and Jason Hammel, got in work Sunday against the Dodgers.
Steve Dilbeck is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.