ST. LOUIS -- Adam Wainwright didn't want to spill the secret, so he talked his way around why he only went three innings in Thursday's intrasquad game despite having the arm strength to go at least five innings.

"I think word is out, right?" Wainwright questioned reporters. "I'll let Shildt talk about it. I don't want to be the guy who breaks news."

No, it wasn't anything physical. The team just changed the plans to better align with the schedule.

"He'll be our number two starter," manager Mike Shildt confirmed later on the Zoom call. "We just made sure we got him in line for that and abbreviated him a little tonight."

Wainwright will start July 25 against the Pirates at Busch Stadium, following Jack Flaherty's Opening Day start on July 24. After Thursday's shortened outing, the veteran right-hander will ramp up Monday to be in line for Saturday's start.

"He's the most built-up guy we've got," Shildt said. "And then we looked up to set the rotation and realized [Thursday] is an opportunity for him to have a nice, crisp outing and then be able to come back and be set up for Game 2 of the season. He's been pretty sharp."

The Cardinals' rotation is beginning to take shape, and more decisions will come in the next week. The biggest will be how the Cards use Kwang Hyun Kim and Carlos Martínez. The team is adamant about using a five-man rotation, and with Flaherty and Wainwright penciled in already, that leaves three spots open. Miles Mikolas and Dakota Hudson are the presumptive third and fourth starters, although not necessarily in that order, and not yet officially. Kim and Martínez are battling for No. 5.

Kim won Thursday's intrasquad for Cardinals Blue, 5-0, pitching five shutout innings and baffling hitters left and right. He allowed just one hit while striking out five of the 17 batters he faced across 69 pitches. Ten of Kim's 42 strikes came on first pitches. He had 10 swings and misses. Kim flummoxed batters with his four-pitch mix, including a slider he can throw at multiple speeds.

"I don't know what it is," outfielder Austin Dean said. "He's a really tough at-bat. He's got that really deceptive delivery. Good jump on his fastball. Really good breaking stuff."

Kim, a 6-foot-2 southpaw, adds some deception to his delivery with his stride. Wainwright has gotten to know him well after working out with him during baseball's shutdown, but even when pressed Thursday, Wainwright didn't want to give away anything specific about Kim's stuff.

"He's talented, and he's not scared, and he's a good pitcher," Wainwright said. "He changes speeds very well. Knows how to pitch, I'll just leave it at that. He's a very good athlete, and he knows how to pitch. He's a great addition to this team."

Kim is open to being versatile -- starting or relieving. That hasn't changed since he was signed this past winter to a two-year deal. Kim kept that mindset in Spring Training and through the break, when he stayed in St. Louis, adjusting to a new country as his family stayed in Korea. There's a case to be made that his fastball/slider combo could generate swings and misses in late-inning situations.

Watching Kim's live batting practice and intrasquad outings show how uncomfortable he makes hitters during at-bats.

"The best-case scenario for me is pitching as a starter," Kim said through interpreter Craig Choi. "But contributing to the team is the most important thing. If the team wants me as a relief pitcher, I should be ready to be a relief pitcher. The most important thing is contributing to the team's victory."

A strong case can be made for Martínez to start, too, having proven himself in the past as a two-time All-Star starter and an elite arm when healthy. He will start opposite Mikolas in Friday's intrasquad game, giving him another chance to assert himself as a starter. Martínez is also a closer candidate, given that he's one of the most experienced bullpen arms the Cardinals have right now. Shildt said Thursday that Martínez has "earned every right to have the opportunity" to start.

With a week until regular-season games, the Cards have an intriguing rotation decision on their hands: Kim, a new-look lefty? Or Martínez, a proven starter who worked hard to stay healthy over the offseason for this opportunity?

"I don't know how they're going to make a decision on five guys honestly, with the arms that we have in the camp," Wainwright said.