JUPITER, Fla. -- Progress tends to come in flashes for Marlins right-hander Sandy Alcantara. It's all part of the development process for the 23-year-old as he competes for a rotation spot.

Statistically, Alcantara's line looked impressive on Sunday in the Marlins' 5-2 win over the Braves at Roger Dean Chevrolet Stadium. But he is trying to iron out issues with his command and with running up deep counts.

"I thought in the first couple of innings, Sandy was a little tentative," Marlins manager Don Mattingly said. "He wasn't as aggressive as I'd like to see him. All of a sudden, he started getting after it, a lot more aggressive in the strike zone. Having finish on his pitches. It was good to see the end of that."

Alcantara threw 4 1/3 scoreless innings, scattering two hits, with two walks and five strikeouts. He got on track late to fan four of the final six batters he faced. He was lifted after 76 pitches with one out in the fifth inning.

The right-hander issued a leadoff single to Ozzie Albies on the game's first pitch, and he had runners on first and third but struck out Alex Jackson on a 90-mph changeup to end the threat.

"You just want to put [out] that sense of urgency that right out of the gate you want to be good," Mattingly said. "You can't groove into starts. You'd like for him to be aggressive. All of our guys, you want them to come out of the gate aggressively, and be on the hunt."

When it comes together more quickly Alcantara will cement himself in the rotation. For now, he's still learning and refining his delivery and off-speed pitches. On Sunday, he unleashed an impressive changeup to go with a fastball that touched 97-98 mph.

"I go to the mound and try to do the best I can," Alcantara said through an interpreter. "Sometimes you have good days, sometimes you have bad days. It's part of the routine."

Breakout day for O'Brien

One swing, four runs. It's that type of impact that Peter O'Brien presents that explains why he's a front-runner to be the Marlins' Opening Day right fielder.

O'Brien blistered a grand slam off left-hander Kolby Allard in the fifth inning on Sunday. He also added an RBI single in the first inning off Julio Teheran. 

For O'Brien, the 2-for-3, five-RBI afternoon was a relief during a rough Spring Training, at least statistically.

O'Brien entered the game 2-for-23 with 14 strikeouts. But O'Brien's power potential is why the Marlins are giving him a chance to play regularly. Both of his RBI hits came with two outs.

"It's my job to drive those guys in," O'Brien said. "I had two at-bats like that today, with two strikes. It was good. Everything just transferring from my work."

Wallach back in action

For the first time since straining his right quadriceps muscle on Feb. 26, Chad Wallach was back behind the plate on Sunday. 

Wallach caught five innings in his return, and will get a day of rest on Monday thanks to the team's scheduled team day off. 

Wallach, who is on the Marlins' 40-man roster, is competing with Bryan Holaday, a non-roster invitee, for the backup catching spot. Both actually have a chance to be on the Opening Day roster, if Jorge Alfaro (right knee bruise) starts off on the injured list. However, the Marlins are confident Alfaro will be ready.

In the meantime, Wallach will be worked back into shape.

"Get him back out there and get him started, because he looked a little like a guy I thought hadn't played in a while," Mattingly said. "A guy who had been kind of rehabbing. Get him back up to speed, and get him going."

To get Wallach and Holaday work, the Marlins are considering playing both of them on the same day, with the one who doesn't start coming in immediately after.

"We'll get where, until Jorge is back, we may back [Wallach] and Holly up together," Mattingly said. "So Holly is starting one day, and he comes in. Chad starts the next day, and Holly comes in.”

Up next

The Marlins are off on Monday, and return to Grapefruit League action on Tuesday against the Mets at Roger Dean Chevrolet Stadium. Hector Noesi is getting the start for Miami.