Leonard is in his fourth NFL season after spending time with the St. Louis Rams (2007), Cleveland Browns (2007-08) and Carolina Panthers (2009-10). He originally joined the NFL as a rookie free agent with the San Diego Chargers in 2007 out of Fresno State.
After beginning his rookie season on the San Diego practice squad, Leonard was signed by St. Louis from the San Diego practice squad. After being waived by the Rams following a four game stint, Leonard was claimed off waivers by Cleveland. He played in four games for the Browns in 2007 and finished with two total tackles.
He played in all 16 games with four starts for Cleveland in 2008, finishing with 31 total tackles. Leonard went to training camp with Cleveland in 2009 but was traded to Carolina on Sept. 1 in exchange for a sixth-round draft choice in 2010. He was limited to just two games and one start in 2009 before finishing the year on injured reserve due to an ankle injury. Leonard played in two games for the Panthers in 2010 before being released on Sept. 28.