Wainwright, the Opening Day starter and 6-3 with a 3.14 ERA, has been on the 15-day disabled list since early June with a ruptured tendon in the middle finger of his right hand. He threw 4 2/3 scoreless innings in his third rehab start last week, and on Tuesday after a bullpen session told manager Tony La Russa and reporters he was ready to pitch in the majors, saying another rehab effort would be "wasting game bullets."
"I expect to go out and compete and do very well just like I would before I got hurt," Wainwright said Wednesday. "I feel the same -- I feel maybe stronger."
La Russa said team medical personnel and pitching coach Dave Duncan all agreed it was time to bring back the right-hander. The Cardinals were 2½ games behind Milwaukee in the wild card race.
"He feels really good, feels like he's 100 percent ready to go," La Russa said. "He's an important guy on our staff. We've missed him and it's his day to pitch."
Wainwright bumps Joel Pineiro, who had been on track to make the start on Friday. La Russa said Pineiro, who is 3-0 in August and 6-5 overall with a 4.80 ERA, would be used in long relief if necessary if Wainwright falters.
Wainwright didn't think stamina would be an issue, though, after throwing 65 pitches for Double-A Springfield on Friday and leaving the game feeling he had a few more innings in his arm.
"My legs feel good, my arm feels great, so everything is a go," Wainwright said.
The middle finger is a key to Wainwright's grip on his curveball, and was injured by repeatedly locking onto the ball. Now he said it was "perfect."
"I'm snapping the ball as hard if not harder than I have all year," he said, and added jokingly, "It's the strongest middle finger in the league."
Both Wainwright and the Cardinals reiterated that he did not demand to be restored to the rotation. Wainwright was the stand-in closer during the team's 2006 World Series run after Jason Isringhausen underwent hip surgery.
He became the de facto ace last year after Chris Carpenter was shelved by an elbow injury on Opening Day, going 14-12 with a 3.70 ERA. He was putting together another strong season this year before the finger injury in June, but insisted there was no lobbying.
It hasn't hurt that hard-throwing rookie Chris Perez is 4-for-4 in save opportunities since being recalled Aug. 6 from Triple-A Memphis, although La Russa still has not anointed him the new closer.
"It's not like I've got three or four Cy Youngs under my belt and 10 years in the big leagues," Wainwright said. "I think Tony respects me as a player but at the same time the main goal is to win as a team.
"He let me know this is a one start at a time thing."
The Cardinals are expected to place Isringhausen, who twice lost the closer job, on the 15-day disabled list with a season-ending elbow injury, but had not yet done so. Wainwright could take that spot on the roster.
Isringhausen told the St. Louis Post-Dispatch in a text message that he hopes to continue his career, despite the injury. The right-hander, who turns 36 in September, is a free agent after this season.
"Tons of desire," Isringhausen texted the newspaper. "Mind is willing. Just gotta get the body there."
Carpenter, on the DL with a strained shoulder, played catch for the second straight day and was scheduled for a bullpen session on Friday. He's not yet considered close to returning to the rotation.
Information from The Associated Press was used in this report.