The Cleveland Browns put center Alex Mack on injured reserve on Friday after he suffered a season-ending broken fibula.
Browns coach Mike Pettine insisted earlier this week that the team wasn't giving up hope that Mack could make a return before the end of the season.
However, the decision to place Mack on injured reserve suggests that there has been ligament damage which will prolong his recovery period, according to NFL.com.
John Greco is expected to replace Mack at center while Paul McQuistan will move into Greco's guard spot ahead of the clash with the Jacksonville Jaguars on Sunday.