Greco sprained his medical collateral ligament on the second play of Sunday's loss to the Seattle Seahawks. Browns coach Mike Pettine said Greco will not need surgery, but he will be sidelined for Cleveland's games against Kansas City and Pittsburgh.
Greco started Cleveland's first 14 games and the 30-year-old has made 54 starts for the Browns since being acquired from St. Louis in 2011.
The loss of Greco is another blow to Cleveland's line as left guard Joel Bitonio has been sidelined with his second ankle injury.
Struggling rookie Cam Erving replaced Greco on Sunday and will likely start this week against the Chiefs. Erving was the No. 19 overall pick in this year's draft. He has been overpowered at times on offense and especially while blocking for field goals.
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