The right-hander has seen a decrease in his velocity and less life on his pitches contribute to his 0-3 start and 9.88 ERA.
One of those starts came against the Cubs, the team he'll face on Tuesday at what is expected to be a cold Wrigley Field. Wainwright tossed only three innings on April 13, giving up a season-high eight runs on seven hits for the loss.
"He was just sailing in spring and then it seemed like he was right where he left off," said Cardinals manager Mike Matheny. "Every once in a while, you get hit with some adversity, and it could end up pushing you for the rest of the season to make minor adjustments. You never know, but someone like him, I know that those rough spots end up making him better."
Wainwright, who has a career 6-5 record against the Cubs with 4.68 ERA, will be up against Cubs right-hander Jeff Samardzija, who will try and bounce back from a rough outing on Thursday against the Marlins.
Lasting just 3 2/3 innings, Samardzija had trouble throwing first pitch strikes and surrendered five runs on eight hits for his first loss of the season. The loss snapped a career-best five-game winning streak dating back to Aug. 4.
While Samardzija got the win on April 13 against St. Louis, giving up five runs in five innings, the Cubs know how dangerous the Cardinals can be.
"They have a lot of left-handed hitters, switch-hitters, some veterans and quality guys," said Cubs manager Dale Sveum. "It's just like any series -- you have to jump off to some kind of lead to take them out of the game a little bit."
Cardinals: Jay's shoulder injury not serious
An MRI on Jon Jay's sprained right shoulder showed no structural damage, the Cardinals announced on Monday.
Jay took Monday off and will work his way back into the lineup as soon as Tuesday.
"[Making sure there was no added damage] was the biggest thing with the MRI, and that's why I was happy with the results," Jay said. "I can't mess it up any more, so I can continue to push it, which is what I wanted to hear."
Tyler Greene received his second straight start in Monday's series opener against the Cubs, Matheny saying he's been impressed with the second baseman's play as of late.
"Yesterday it looked he was tracking the ball well, wasn't jumping, wasn't swinging at a lot of bad pitches," Matheny said prior to Monday's game. "You see somebody who, their timing looks right, you figure out how to give them an opportunity to get going."
Cubs: Bowden added, Lopez designated for assignment
Rodrigo Lopez was designated for assignment Monday to make room on the Cubs' 25-man roster for reliever Michael Bowden, acquired from the Red Sox in the Marlon Byrd deal.
"If he clears waivers and everything, we want him to be in the rotation down in Triple-A," Sveum said of Lopez, who had appeared in four games with the Cubs and compiled a 5.68 ERA. "Hopefully, that happens and hopefully, he elects to go down there as well."
Cubs pitcher Kerry Wood, on the disabled list with right shoulder fatigue, is expected to start throwing off the mound soon. He last pitched April 13 and received a cortisone shot in his shoulder on Wednesday.
"He feels a lot better," Sveum said Monday of Wood, who was placed on the disabled list Friday, retroactive to April 14. "We'll get him off the mound here pretty quick and see how that goes. He's making a lot of improvement and says he feels great."
The Cubs have combined to score 30 runs in the club's five wins and combined to score 32 runs in 12 losses.