UPDATE (12:30 p.m. ET): The Patriots have signed free agent wide receiver Riley McCarron, a source told ESPN.com’s Mike Reiss. McCarron arrived at practice Friday, wearing No. 84.

ORIGINAL STORY: FOXBORO, Mass. — The New England Patriots added a new wide receiver ahead of Friday’s practice inside Gillette Stadium.

It initially was unclear whether the unidentified receiver, who wore No. 84, had been added to the 53-man roster or to the practice squad.

Just two players were missing from the session: running back Rex Burkhead (ribs) and defensive tackle Vincent Valentine (knee). With Burkhead missing all three practices this week and Valentine sitting out two, it’s unlikely either will play Sunday against the Houston Texans.

Offensive tackle Marcus Cannon was present at practice, but it was unclear whether he was a full participant. Cannon, who is dealing with a concussion, warmed up with his teammates Thursday but was listed as “did not participate” on the Patriots’ official injury report.

If Cannon cannot play Sunday, either Cameron Fleming or LaAdrian Waddle would start opposite left tackle Nate Solder.

Friday’s practice marked the first time the Patriots took the field at Gillette since they replaced the turf playing surface following Week 1.

Thumbnail photo via Chuck Cook/USA TODAY Sports Images