"It's hard to imagine getting him back into the rotation with, realistically, 13 days left," said John Mozeliak, president of baseball operations.
Because of that, the Cardinals plan to continue starting rookie Jack Flaherty, who has made three appearances since being called up at the start of the month. Flaherty, whose next start will be on Tuesday, is in line to make three starts over the team's final 13 games. None of those would be against the Cubs.
If the Cardinals get to a point where they aren't comfortable adding to Flaherty's already career-high innings count, Mozeliak said the club could plug John Gant in as a spot starter.
As for Wainwright, he'll try to make a late-September impact out of the bullpen for the second time in three seasons. In 2015, he was returning from an Achilles injury. This time, Wainwright is coming off a month missed due to a right elbow impingement.
He's expressed feeling progressively better each of the three times he's thrown off the mound in the last week, including on Sunday, when he faced Luke Voit, Alex Mejia and Magneuris Sierra during a morning session of live batting practice at Wrigley Field.
"I know when I'm doing good I'm getting grounders and punchouts," Wainwright said. "Today I made some good pitches. I was pretty pleased with it. … If I had that stuff in those other games, I'd still be pitching."
In addition to Wainwright's availability, the Cardinals expect to get a boost in their next series from having Seung Hwan Oh and Jedd Gyorko back at full strength. Oh hasn't pitched since Sept. 7 because of lingering hamstring tightness. Gyorko has been available as a pinch-hitter for a few games and should be cleared to play the field and run the bases by Tuesday.
• Triple-A Memphis has one final chance on Sunday to clinch its best-of-five Pacific Coast League Championship series. El Paso evened the series with a 5-1 victory on Saturday. Memphis, which has scored just two runs in its last 29 innings, got its run on an Aledmys Diaz RBI double.
• Once Memphis' season ends, the Cardinals plan to promote a few additional players to their Major League roster. That could come as late as Wednesday, as the Redbirds would play in the Triple-A Championship game on Tuesday if they defeat El Paso for the PCL crown.