PITTSBURGH -- While Cole Tucker was at the Pirates’ Minor League complex in Bradenton, Fla., working to revitalize his offense, the club had him take live batting practice against some of the pitchers it planned to send to High-A and Double-A.

One of them was Roansy Contreras. Tucker had seen flashes of him at Spring Training, but when he stepped into the box to face the right-hander it was a different story.

“It was like, ‘Hey, go get ‘em!” Tucker recalled. “‘Try out this new stuff. Here’s 97-99 mph. Go get ‘em!’ ... He’s sick.”

Now, after a season of ups and one big down he had to overcome, Contreras made his long-awaited -- and maybe somewhat unexpected -- Major League debut at the young age of 21, announcing his presence with three scoreless innings to start the Pirates' 3-2 loss loss to the Cubs on Wednesday night at PNC Park.

What’s in Contreras’ arsenal? First and foremost, high heat. The Pirates’ No. 6 prospect, per MLB Pipeline, touched 97.8 mph on the radar gun in the first inning, making him the only Pirates pitcher to hit that velocity in a start this season. And his four-seamer completed three of his four strikeouts.

Contreras has an above-average changeup, but he largely kept it in his back pocket. Instead, the slider was his most used secondary pitch, one that has been the biggest work in progress of any of his offerings. It drew three whiffs, plus a strike three swinging from David Bote.

Contreras' stuff was electric, and pointed toward what the Pirates and their fans hope he can become. However, it wasn’t a scuff-free start.

Rafael Ortega sent Contreras’ second pitch of the game for a single, then the right-hander left an 0-2 fastball too close to the middle for Willson Contreras two batters later -- another single. To begin the second inning, Contreras threw six balls in a row before settling in for two straight strikeouts.

“This kid shows a lot of growth in a lot of areas,” manager Derek Shelton said. "Tonight we saw a young kid that never got away from what his plan was. … He came back and executed pitches, and that's a really good sign for the Pirates moving forward.”

And the outing didn’t last long, though that was to be expected. Contreras threw 46 pitches, a fair bit below the 64 he threw in his last start at Triple-A Indianapolis. But given that he sustained right forearm and elbow discomfort in June and the fact that he returned from the injury as quickly as he did, and as a hard-throwing starting pitcher, is a credit to both him and the Pirates’ medical training staff.

“It's awesome to see a young man have the confidence in himself to become aware of an injury, to notify the medical staff, and then to … watch the true collaboration of a player, a medical staff, a strength staff, a pitching department,” said Pirates director of sports medicine Todd Tomczyk. “[It’s] a true organizational win for me, but the biggest winner here is Roansy.”

Part of the reason Conteras was held back was the number of innings he’d thrown around the injury, with only 58 across Double-A and Triple-A (and just one start in Indianapolis). In fact, it almost appeared Contreras would finish the year at Triple-A.

But the Pirates need innings right now with an injury-marred pitching group, and Contreras’ numbers were phenomenal, pointing toward something GM Ben Cherington said he weighs in callups.

“If a player is not being challenged at a level, just dominating to the point where they’re not getting anything out of the competition, then we would want to move that player no matter how much was left in the season,” Cherington said last month.

Contreras looked well at ease at Double-A Altoona, especially before his injury. He threw six no-hit innings on May 11 against Binghamton. He had a 12.6 strikeouts per nine innings ratio with the Curve. He allowed more than three earned runs only once.

So on Wednesday, Contreras got a small but healthy dose of challenge in his debut. And he passed his first test.

“This past offseason and the offseason before that, I had been preparing for this moment,” Contreras said. “I’d taken my preparation very seriously and I’ve been very diligent in my preparation.

“I’ve got to be honest with you: I’m not shocked [I’m here]. A huge part of that is that I really believe in all the hard work and sacrifices I’ve dedicated to this game. To see the results, it’s huge [and] it’s a blessing.”