BUFFALO, N.Y. — Bills defensive tackle Marcus Stroud has signed a two-year contract extension potentially worth $16.5 million, the player's agent told The Associated Press.

Drew Rosenhaus said Tuesday his client's extension includes $12 million in guaranteed money, locking up Stroud through the 2012 season. Stroud was a Pro Bowl alternate after completing his first season in Buffalo after being acquired in a trade with Jacksonville.

Stroud stands to earn up to $28 million over the next four years should he achieve all bonuses.

The Bills did not immediately respond to a request for comment.