MILWAUKEE -- Merandy Gonzalez, one of the Marlins' top pitching prospects, was called up from Double-A Jacksonville on Thursday to provide depth in the bullpen.
Ranked by MLB Pipeline as the Marlins' No. 15 prospect, Gonzalez is getting his first big league callup because Chris O'Grady was placed on the 10-day disabled list Thursday with a left shoulder strain.
Gonzalez threw two scoreless innings in his Major League debut on Thursday night, as the Marlins fell, 12-3, to the Brewers.
With O'Grady on the DL, the Marlins don't have a left-hander in their bullpen. Gonzalez, who is being groomed to start, will fill a bullpen role.
"Merandy, for now, will be in that [long-relief] role," Marlins manager Don Mattingly said.
Tyler Cloyd and Gonzalez are now the Marlins' two primary long relievers. But Cloyd, who threw 87 pitches in relief on Monday in a 12-1 loss at the Yankees, won't be available for a few more days.
"We think [Gonzalez], obviously, is a starter," Mattingly said. "He was starting in Double-A. He seemed like the right guy for us right now. Obviously, there were other options. But right now, he will be throwing early, kind of like Jarlin [Garcia] was doing earlier in the season. If somebody gets in trouble early, you have a chance for a longer outing."
Garcia opened the season in long relief, but has since moved into the rotation.
The Marlins acquired Gonzalez from the Mets last July in the AJ Ramos trade. In two starts at Jacksonville, Gonzalez was 0-1 with a 4.50 ERA, logging 10 innings with seven strikeouts and four walks.
"When I got the call, it was one of the more emotional moments of my career," Gonzalez said. "It's been five years since I've wanted to get the call and be up here. It was a great moment."
After joining the Marlins' system last season, Gonzalez threw 24 1/3 innings with a 1.11 ERA in five appearances (three starts) for Class A Advanced Jupiter.
Gonzalez was with the big league club in Spring Training, but the intention was to get him to Double-A so he could work as a starter.
"One of the biggest thing I was working on was controlling the inside part of the zone," Gonzalez said. "If you can control that area, you really aren't giving the hitters much chance to have success. That as well as working on my breaking pitches."
O'Grady has a 6.43 ERA with seven strikeouts in eight appearances over seven innings. He last appeared on Monday in a 12-1 loss at the Yankees. O'Grady returned to Miami and is being evaluated by team physician, Dr. Lee Kaplan.

Not having a left-handed option in the bullpen is not ideal, but Mattingly said that the call was made to get the best fits at this time.
"I'd like to have three," Mattingly said. "But right now, we don't have one. It's always tough without the lefty. It makes it harder for you. We've always said we'd rather have the best guy out there than a lefty just because he's a lefty."
Worth noting
• Wei-Yin Chen (left elbow) made his first rehab start for Jupiter on Tuesday. He allowed one run over 2 2/3 innings and struck out four. Chen was set to throw a bullpen session on Thursday and is expected to make another rehab start.
• Martin Prado (left hamstring) started his rehab assignment and is scheduled to play six innings at third base for Jupiter on Thursday.
• Dan Straily (right forearm strain) threw five innings in a rehab start on Wednesday for Jupiter and will be evaluated on where he will next pitch.
• Shortstop JT Riddle (right shoulder tendinitis) is expected to play three innings at shortstop on Friday in an extended spring training game.