The New England Patriots on Tuesday worked out former Southern California defensive lineman Armond Armstead, a source confirmed.

Armstead, 22, played three seasons for USC, from 2008-2010, starting 17 games and recording 59 tackles. His attorney claims Armstead suffered a heart attack in early 2011, the alleged result of team doctors treating him with the painkiller Toradol. He was not medically cleared to play in 2011, and sued the university in August 2012 for unspecified damages.

Armstead went undrafted in the 2012 NFL draft and later signed with the Toronto Argonauts of the CFL. He led the Argonauts in sacks this past season and was named a CFL all-star. Armstead was released by Toronto on Friday, reportedly to pursue NFL opportunities.

Listed by the CFL at 6-foot-5, 298 pounds, Armstead reportedly drew interest from the Patriots prior to last April's draft, and could be on their radar for a spot on their offseason roster. NFL rules prohibit teams from signing players from CFL rosters within the same season, so Armstead cannot join the Patriots for the playoffs.

Tom E. Curran of Comcast Sports Net first reported the workout.