ST. PETERSBURG -- Manager Don Mattingly has no doubt that rookie right-hander Edward Cabrera is going to be a good Major Leaguer, and that’s exactly what he reiterated to MLB Pipeline’s No. 30 overall prospect prior to the third inning on Friday night. 

Cabrera took heed, finishing strong after starting shaky in the Marlins’ 8-0 loss to the playoff-bound Rays at Tropicana Field.

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The 23-year-old recorded the first two outs of the first inning on 10 pitches, then proceeded to throw another 30 before escaping the frame. The trouble began with a walk to Ji-Man Choi, followed by a Nelson Cruz single and an Austin Meadows walk. Randy Arozarena then sent a full-count, 93.1 mph changeup to left for a bases-clearing double.

“I believe the pitches were not landing, so it's something that's going to happen,” Cabrera said via an interpreter. “What I have to do is maintain my composure and focus on trying to finish the inning. I'll say the key will be to stay calm. Once you make a mistake, you’ve got to think about the next guy at the plate because [when] you start thinking too much, the game starts spinning, it gets fast.”

It looked like more of the same in the second, as Cabrera walked two in a row to open the frame. But after a mound meeting, he retired the next three. When he returned to the dugout, Mattingly had his chat with the flamethrower.

Cabrera capped his outing by striking out Arozarena on three pitches to end a clean third. He certainly wasn't sharp, but there were some positives to take away from his latest appearance. 

He kept on-base machine Wander Franco from reaching in both of their matchups. And while Cabrera walked four batters, he also struck out six -- one shy of his career high set in his last start. 

“It was a little like some of the conversations with Trevor [Rogers] when he had a rough outing going [last year],” Mattingly said. “I knew that we were going to be quick with him even in that third. I said, ‘Hey, it started off bad. Let’s just go out and make pitches like you have your whole life. Just make pitches out there, and that’s it. You're going to be fine.’ 

“And he's going to be fine. He’s actually going to be really, really good. Nights like tonight, you hate to say they’re good for him, but they are. They let you know. That’s all I said.”

Mattingly knows there will be growing pains -- that’s part of being a young player in the game. But he is confident Cabrera will come out strong on the other end because of his composure. This time in The Show is mainly for Cabrera to gain valuable experience heading into the offseason, so when he arrives for Spring Training, he will have a solid foundation for 2022. 

That will include getting ahead of batters -- something he struggled to do in that first inning. Switching up his pitch usage to keep clubs honest, especially one like Tampa Bay with the second-most runs in the Majors, will be another key.

Entering Friday, lefties were slashing .333/.458/.718 with four homers vs. Cabrera, while righties were slashing .194/.341/.361 with one homer. That plays into opponents going 1-for-21 (.048) with nine strikeouts vs. his slider, his main weapon vs. righties, but 12-for-31 (.387) with four K’s vs. his curve and changeup, his main pitches vs. lefties. In the series opener, Cabrera tallied five of his six strikeouts on the slider. His low percentage of fastballs can make him predictable, thus impacting the efficacy of his other selections.

Through six MLB starts, Cabrera has a 5.79 ERA and no wins. Command has been an issue, as he has issued at least three free passes in five of his six starts (6.56 BB/9). On the flip side, after fanning just nine batters through his first four starts, he has 13 combined in his past two.

Does Cabrera feel like he’s not living up to expectations? How does his performance compare with what he had hoped?

“When you're here, you don't want to be satisfied with anything,” Cabrera said. “You want to continue to keep working and get better. Right now, things are not going the right way, but you've got to continue to keep working and develop to get to that potential.”