There will be two reunions at Busch Stadium this weekend.

The first comes in the form of the Cubs coming to town for the first time since the 2019 season, as the pandemic-shortened '20 season resulted in all matchups of the rivalry taking place within the confines of Wrigley Field. 

The second is that Cardinals right-hander Miles Mikolas is slated to make his much-anticipated return to a big league mound Saturday, the club announced prior to Wednesday’s series finale against the Pirates. Mikolas' start will mark his first time on a big league mound since the 2019 National League Championship Series.

And there’s a quasi-third reunion, as well. Carlos Martínez (right ankle sprain) is also slated to return off the injured list for Friday’s series opener (with Adam Wainwright pitching in the finale Sunday).

When Martínez and Mikolas both rejoin the fold, it’ll mark the first time this season that the Cardinals have their planned Opening Day rotation at full health.

“It's exciting, right?” said manager Mike Shildt. “It's been a little bit of a journey for [Mikolas]. … It's exciting for him to get back in the rotation and perform and pitch -- doing what he loves to do.”

Mikolas is coming off surgery that repaired the flexor tendon in his right forearm during Summer Camp last July, before he strained his right shoulder during a live batting practice session during Spring Training. It was a long road back for the right-hander, who went without facing batters from Feb. 25 until mid-April.

But the 32-year-old was in full-swing for his three rehab stints with Triple-A Memphis, firing six shutout innings on 80 pitches his last time out, blasting a two-run homer to boot.

“Almost a year since, you know, like a meaningful inning,” Mikolas said after his first rehab start with Memphis on May 5. “It was fun. We're all excited to be out there.”

Not only will the return of Mikolas and Martínez, who sprained his ankle on the dugout stairs while celebrating Jack Flaherty’s home run on May 7, signal a fully clean bill of health for the rotation, but it comes at a time in which the club begins its second stretch of 17 consecutive games without an off-day.

The Cardinals used a six-man rotation in the last iteration of the gauntlet, welcoming No. 9 prospect Johan Oviedo to the fold for such starts. Now it’s a natural six, with John Gant slated to move to the back-end of the crop of starters.

“Our starters have given us, most every night, an opportunity to win baseball games,” Shildt said. “It's been a nice benefit, because it doesn't feel like we have to go to a five-man and turn the rotation over and put a little extra strain over the course of a longer season on our guys.”

Mundito’s night of firsts

Anyone with a rudimentary handle on the Spanish language could have easily gathered what Edmundo Sosa has done to stay ready for an opportunity like the one he has now, with some semi-regular playing time at shortstop in his lap with Paul DeJong on the injured list.

“Trabajo,” Sosa said after Tuesday’s 5-2 win. “Trabajo fuerte.”

Work. Work hard.

That paid off for the 25-year-old infielder Tuesday, who, when making just the fifth start of his career, laced his first career extra-base hit and RBI -- a run-scoring double in the third inning.

There are three metrics that MLB Pipeline uses for graduating players from prospect status: 130 at-bats for position players and 50 innings pitched for hurlers -- or 45 days on the active roster regardless of position, if the two former bars are not cleared.

Sosa, who began the year as the club’s No. 18 prospect per MLB Pipeline, has since graduated from prospect status -- solely because of the third metric. Put another way: He’s been a big leaguer but has not played much in the big leagues.

That has the chance to change now. Sosa made his second consecutive start in place of DeJong on Wednesday, and though the latter is not expected to miss a lengthy amount of time, it’s been extra work in the cage with assistant hitting coach Jobel Jimenez or talking shop with Willie McGee that’s allowed Sosa to stay ready.

“I take every day as if I was starting that day,” Sosa said. “My overall mindset stays the same, independent of what's going on.”

“You can tell a guy to stay ready all you want, but he gets out there, works with [first-base coach and infield coordinator Stubby Clapp] … it’s pretty impressive,” Shildt said. “He does it with a real intent and there's a real focus, there's a lot of intentionality behind everything he's doing. There's a mental and physical commitment to being ready and to his credit, he's done it and now he's getting the opportunity.”