The Patriots have signed former Southern Cal defensive lineman Armond Armstead, per sources. Armstead played for the Toronto Argonauts of the Canadian Football League this past season, leading the team in sacks while earning all-star recognition.

Armstead, 22, played three seasons for Southern Cal, 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.

After going undrafted in 2012, Armstead signed with the Argonauts, in part to prove he was healthy.

ESPN NFL Insider Adam Schefter wrote on Armstead earlier this month: "In the 6-foot-5, 300-pound Armstead, an NFL team will be getting the equivalent of a high draft pick months before the April draft."