LeBlanc was called up to replace right-handed reliever Edward Mujica, who was placed on the 15-day disabled list with a fractured right pinky toe following Saturday's game.
LeBlanc, who started 16 games with the Zephyrs this season, will be used in a long-relief role with the Marlins.
"This kid can do a lot of things," Marlins manager Ozzie Guillen said. "He's done relief in the past, obviously a starter. We kept him in the Minor Leagues in case something happened with somebody in the rotation, that's the guy we're going to grab. ... That's a guy that can help us, just in case something comes up."
The Marlins opted to recall LeBlanc due to a lack of available short-relief options. Guillen said right-handed pitcher Alex Sanabia is dealing with a rib injury and righty Sandy Rosario is on the 15-day disabled list with a strained right quad. The Marlins didn't want to recall righty Chris Hatcher again because they want to continue to develop him in the Minors.
Despite the long-relief role, Guillen said he would prefer not to use LeBlanc in matchups against left-handed hitters. In 16 games with New Orleans this season, left-handed batters were batting .313 in 27 innings against LeBlanc, while righties hit just .216 in 71 2/3 frames.
"I'd rather see him against righties instead of lefties," Guillen said. "He's not a lefty-lefty guy, that's why I think we got [lefties Mike] Dunn and [Randy] Choate."
With Mujica sidelined for at least two weeks and LeBlanc as the long reliever, Guillen said the rest of the relievers' roles will move up an inning. Steve Cishek will be the eighth-inning setup man, while Dunn, Choate and righty Chad Gaudin will all be used in the seventh inning.
In particular, Guillen wants to take advantage of the way Dunn has thrown since the team recalled him from New Orleans on June 21. In six appearances since rejoining the Marlins, Dunn has pitched 5 2/3 shutout innings, striking out four and walking none.
The lefty struggled with command earlier in the season, but he is now throwing his fastball for strikes while also effectively using his secondary pitches to keep hitters off balance.
"[The Marlins have] been waiting for this type of pitcher the last few years," Guillen said. "It's a pleasure to watch. I have a lot of confidence in him, and hopefully he continues to throw the ball that way."
Tom Green is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.