Manager Mike Matheny said that the organization's level of concern about the injury is "not as high now that we have some results back."
The Cardinals will proceed cautiously over the next few days, though Matheny did not rule out Wainwright making his next scheduled start on Monday. If needed, the team could push that start back another day, too, because of Thursday's off-day.
"We're going to wait and see how everything goes," Matheny said. "We're going to take some more notes and listen to the doctors. I think it was the right medical move to get him home as quick as we could to make sure there wasn't anything more going on than what we thought."
Wainwright pitched seven scoreless innings on Tuesday, though even he admitted after that he was pitching with "subpar-to-average stuff." He improvised on a slider in order to compensate for trouble with his cutter, sinker and curveball, while still managing to blank the Rays.
Though Wainwright had few stress-free innings, Matheny removed his ace after 92 pitches, an indication that something might be slightly amiss. Wainwright did not alert the Cardinals' medical staff to any discomfort until after he was taken out of the game.
"It was good, but it was a little different," Matheny said. "I think that's kind of our job, because you get a guy into warrior mode, which he gets every fifth day, if I go up and ask, I'm not going to get a real good answer anyhow. In the seventh, I noticed a little bit with the [drop in] velocity. It just looked like he was working real hard. And then when I approached him and I told him I think that might be good, I got zero fight. I knew he had been grinding."
Despite pitching at less than 100 percent for most of the season as he has battled this issue and recurring allergy problems, Wainwright has been arguably the National League's best starter. He became the first in the league to reach nine wins with Tuesday's victory, as well as the first to pitch 100 innings. His 2.15 ERA is fourth-best in the NL, and he has not allowed a run in seven of his 14 starts.
Wainwright has carried a substantial workload since returning from his season missed due to Tommy John surgery. He led all pitchers with 276 2/3 innings pitched (regular season plus postseason) in 2013. Only Detroit's Justin Verlander has thrown more innings than Wainwright's 590 2/3 since the start of the 2012 season.
Since Wainwright had shown an ability to not just pitch through discomfort but dominate, the Cardinals had not pulled the reins on him until now. He is averaging more than seven innings per start this season, but has maintained impressive efficiency throughout. Wainwright has averaged 102 pitches per outing, topping out at 117 with eight shutout innings on May 25.
"He explained it as something that he has had and has thrown through before," Matheny said. "It was in the right spot, and he knows exactly how to manipulate it and how to get around it. Doctors looked and concurred that it was in the right spot."