Patriots DT Armond Armstead has retired from the NFL.

Patriots DT Armond Armstead (illness) is on pace to be ready for April OTAs. Armstead was expected to be the Patriots third defensive tackle in 2013, but he missed the entire year due to a mysterious infection. The talented interior pass rusher also sat out his 2011 season at USC following a heart attack. If healthy, Armstead has a chance for a real role this season -- especially if Vince Wilfork ends up gone.

Patriots placed DT Armond Armstead on the reserve/NFI list. Armstead has been dealing with a non-football illness related to surgery he underwent to treat an infection. No other details are known. The Pats will hold out hope Armstead is able to contribute by midseason or late in the year.

Patriots DT Armond Armstead (active/non-football illness) underwent surgery to treat an infection Monday. The area where the infection resided is unknown, but it's not related to his past heart problems. Armstead doesn't have a timetable for his return, but the team expects him to make a full recovery. He's competing to be the No. 3 or 4 defensive tackle behind projected starters Vince Wilfork and Tommy Kelly.

According to ESPN Boston, the Patriots have "high hopes" for first-year DL Armond Armstead. Armstead missed the 2011 season at USC after suffering a heart attack, and he went undrafted. He played in the CFL with the Toronto Argonauts last year and registered six sacks at 6-foot-5 and 298 pounds. Multiple front office men believe Armstead, 22, would have been a third-round pick had he not suffered the heart attack. Expect him to be a situational pass rusher this season.