PHILADELPHIA -- On the eve of his Major League debut, left-hander Génesis Cabrera spoke to the media with the help of a translator -- except when asked if he was nervous for his Wednesday start against the Phillies at Citizens Bank Park.

"A little bit," Cabrera replied in English, with a laugh.

Cabrera, the Cardinals' No. 8 prospect, according to MLB Pipeline, will get the first crack at filling the starting spot vacated by Michael Wacha's move to the bullpen. It's been quite the journey to the Cards' rotation for Cabrera since being acquired from the Rays last summer as part of the Tommy Pham trade.

The 22-year-old lefty turned heads in the Dominican Winter League, where Cabrera racked up 21 strikeouts over 14 1/3 innings out of the bullpen, to go along with a 1.26 ERA. More importantly, perhaps, the Cardinals realized he was hitting 98 mph with his fastball after sitting at 92-95 mph as a starter.

Yet after reporting to big league camp with hopes of winning a starting job, Cabrera allowed eight runs (seven earned) over three innings in four Grapefruit League appearances. He walked four and struck out just two. Cabrera then began the year in the bullpen at Triple-A Memphis, where he allowed seven runs over 4 2/3 innings in two appearances before being moved back to the rotation.

Though Cabrera has never wavered on wanting to be a starter, he admitted that he learned a valuable lesson from pitching out of the bullpen.

"Being able to pitch in the Dominican Republic as a reliever, and throw everything I have for one inning, allowed me to see my full potential and just how hard I can throw," he said through a translator.

The concern, however, has never been about Cabrera's velocity. Instead, the Cards are hoping to see the southpaw command the strike zone, something the organization was encouraged by in his last couple outings with Memphis.

Cabrera walked just two batters over 12 innings in his last two starts, putting up a 5.0 strikeout-to-walk ratio and a 4.1 walk percentage. That's a far cry from his 1.8 strikeout-to-walk ratio and 12.8 walk percentage in his first seven appearances of the season.

"I focused on the command of my fastball," Cabrera said. "I think that was one of the keys to my success. I think the major thing that worked during my period in Memphis was to stay focused and have the command of that fastball."

Manager Mike Shildt said those recent improvements are the main reasons Cabrera's name jumped to the top of the list when the Cardinals consulted their player development staff when deciding on Wednesday's starter.

“We got glowing reports from all parties in our system that he was the guy for this opportunity," Shildt said. "We’re excited to see him pitch.”

Whether Cabrera sticks in the rotation will obviously be dictated by performance, but it's also worth noting that Austin Gomber and Alex Reyes are both on the mend.

Despite the brief bullpen role to begin the season, Cabrera has been stretched out enough that he won't have any limitations against the Phillies. He completed six innings in each of his last three starts with Memphis, while throwing at least 90 pitches each time out.

"We like to tell our starters the proverbial, ‘Here’s the ball, give it back when you’re done,’" Shildt said. "But he’s set up to go like a normal starter would go, and we’ll evaluate what the competition looks like."

Though Cabrera has had his ups and downs over the past six months, from his impressive winter to his disappointing spring, he said it was all worth it when he found out he'd be getting the call. He said the moment was made more special for his family because he was notified on Sunday, which was Mother's Day in his native Dominican Republic.

As for those admitted nerves, Cabrera doesn't expect them to affect his performance.

"A little bit, but that’s obviously something that happens," he said. "To be here for the first time in the Major Leagues, there’s always going to be a little bit of nerves. But I’m going to control it and hopefully everything will be OK."