The Patriots have placed tight end Rob Gronkowski on injured reserve, officially ending his 2013 season after he suffered a torn ACL and MCL, according to ESPN NFL Insider Adam Schefter.
The team also officially re-signed tight end D.J. Williams, as Mike Reiss reported earlier today.
Gronkowski becomes the fifth starter to land on injured reserve this season, joining nose tackle Vince Wilfork, linebacker Jerod Mayo, defensive tackle Tommy Kelly and offensive tackle Sebastian Vollmer.
He left the team's game on Sunday in the third quarter after taking a hit to his right knee from Browns safety T.J. Ward.
Gronkowski played in seven games this season, totaling 39 catches, 592 yards and four touchdowns.
By re-signing Williams, the Patriots add another veteran reserve at the position. The team also has Michael Hoomanawanui, Matthew Mulligan and fullback James Develin, who has taken reps at the position at times this season.