Should the Cardinals squander their three-game lead over the Pirates in the NL Central, Wainwright would then be unavailable to start the Wild Card Game on Tuesday.
With Wainwright likely pegged for the NLDS opener, every other St. Louis starter would be available to pitch Game 2 on Friday, with all but Kelly getting additional days' rest.
The 32-year-old Wainwright leads St. Louis in innings pitched and has tossed a career-high 236 1/3 this season. His next start will match his 2009 career high of 34. If Wainwright earns his 19th win on Saturday, it will tie him with Washington's Jordan Zimmermann for the NL lead.
"What had as much factor of anything was sitting and talking with [Wainwright] about what he feels gives him the best chance to be successful, and just continuing to treat the ace of the staff and as if were the ace of the staff," Matheny said. "[We] continue to listen to these guys and how their body feels, and he feels good. He's been on regular rest for a while. I think he's ready to just stay here."
Chad Thornburg is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.