Denver Broncos center Dan Koppen left Sunday's practice with an injury, according to the Denver Post's Mike Klis.

Now, Jay Glazer of FoxSports says the Broncos fear that Koppen has torn his ACL.

The Broncos are also likely without J.D. Walton for the season, and now with Koppen possibly on the shelf too, Denver is in the market for a center, who can step in and protect Peyton Manning.

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Terry McCormick covers the Titans for TitanInsider.com