JUPITER, Fla. -- Jarlin Garcia started 89 games over six Minor League seasons. For the Marlins in 2017, the rookie appeared in 68 games, all out of the bullpen. 
Transitioning back to the starting rotation is the challenge Garcia could be facing in 2018.
"I don't think it's such a big transition for him," said manager Don Mattingly prior to Saturday's game with the Mets at Roger Dean Chevrolet Stadium. "I think the biggest challenge that Jarlin has is fastball command."
Garcia threw two innings in relief on Saturday in the Marlins' 1-0 win over the Mets at Roger Dean Chevrolet Stadium. Garcia had an efficient 27-pitch, 16-strike outing and faced the minimum, although unconventional in doing so.
He had trouble with the lead-off batters of each inning, yielding a single to Juan Lagares on his first pitch in the third inning before erasing him on a doubleplay ground ball. He hit Philip Evans with a pitch to start the fourth. And after a strikeout of Peter Alonso, Evans was gunned down on a steal attempt of second by Marlins catcher J.T. Realmuto.
It was his second outing of the Spring. He threw two innings against Houston on Monday, striking out two while allowing no runs and one hit.
After having seen the 25-year-old left-hander for a season, Mattingly has so far been impressed with his raw talent and now hopes to simply refine it.
"When you watch his pens and stuff; him getting the ball where he wants and having control of his delivery, because it can be a little violent at times," Mattingly said. "When he gets control of that, he throws the ball where he wants.
"Right now, I still see a lot of misses. When he's trying to go away, [the pitch] is running into the middle of the plate. He's trying to go in and it runs off the plate."
There's no question about Garcia's talent. Harnessing it is going to be the key moving forward.
"He's got the weapons, it's just a matter of him just understanding his delivery - what causes what - continued improvement with his fastball command," Mattingly said. "That's what's going to take him to a different level. If he has fastball command, he has a chance to be one of those guys that can be really solid, really good big leaguer."
Garcia threw 53.1 innings (1-2, 4.73 ERA) for the Marlins last season, striking out 42 while issuing just 17 walks.