On May 23, 2009, Leroux was recalled by the Marlins. He made his MLB debut three days later against the Philadelphia Phillies. He was optioned the next day when Brett Carroll was recalled. He rejoined the Marlins when Matt Lindstrom went on the disabled list. In his third appearance, he recorded his first MLB strikeout, which was of Cristian Guzmán. In 5 games with the Marlins, he had a 10.80 ERA with two strikeouts in innings Leroux opened 2010 with the New Orleans Zephyrs of the Class AAAPacific Coast League, but was recalled on April 14. Leroux was placed on the 15-day disabled list on May 19 with a right elbow strain. He missed 26 games, and was subsequently assigned to New Orleans. He was recalled on September 3 when the rosters expanded.
Pittsburgh Pirates
Leroux was claimed off waivers by the Pittsburgh Pirates on September 13, 2010. In 23 games with both teams, he went 0-1 with a 6.75 ERA with 22 strikeouts in innings. Leroux began 2011 with the Indianapolis Indians of the Class AAA International League, but after a poor start, he was demoted to the Altoona Curve of the Class AA Eastern League. After a 5-game stint with Altoona, he returned to Indianapolis. On July 3, Leroux was recalled to Pittsburgh, replacing Brad Lincoln. He was optioned to Indianapolis on July 22, but was recalled 5 days later, only to be placed on the disabled list with a left calf strain 2 days after that. He was activated from the disabled list on August 22, and remained on the roster for the rest of the season. In 23 games with the Pirates, he went 1–1 with a 2.88 ERA. Prior to the 2012 season, Leroux was placed on the 60-day DL with a right pectoral strain. He rejoined the club as a September call-up after rehab and an assignment to the AAA Indianapolis Indians. In 10 games with the Pirates, he had a 5.56 ERA with 12 strikeouts in 11.2 innings. Leroux made the 2013 Opening Day roster with the Pirates, but was designated for assignment on April 12 after pitching in 2 games. He elected free agency on April 17, 2013.
On January 27, 2014, Leroux signed a minor league contract with the New York Yankees. The deal included an invitation to major league spring training. Leroux began the season with the Scranton/Wilkes-Barre RailRiders of the International League. He made his Yankee debut on April 29, 2014. He was designated for assignment on May 3, 2014. He was called back up by the Yankees on July 23, 2014, but was designated for assignment two days later. He was called back up a third time on August 11, 2014 and again designated for assignment two days later. After the 2014 season, he became a free agent. After pitching two innings, he earned a 22.50 ERA, a loss, and didn't earn a win.
Later career
Leroux signed a minor league deal with the Milwaukee Brewers on January 26, 2015. He began the season with the Colorado Springs Sky Sox of the PCL. On May 18, 2015, he was traded to the Philadelphia Phillies for cash considerations. He spent the rest of the season with the Reading Fightin Phils of the Eastern League and the Lehigh Valley IronPigs of the International League. On April 3, 2016, Leroux was traded to the Toronto Blue Jays for cash considerations, and assigned to the Buffalo Bisons of the International League. He was released on August 28. After playing for the Canadian national team in the 2017 World Baseball Classic, Leroux retired from baseball.
Leroux throws three pitches: a four-seam fastball and two-seam fastball in the low-to-mid 90s, and a slider in the low-to-mid 80s. He also used to throw a changeup to left-handed hitters, but he dropped it after the 2011 season to simplify his pitching approach.
Personal life
In 2017, Leroux was cast as the Bachelor on The Bachelor Canada.