In 2005, after Takeo Spikes went down with a season ending tear of the Achilles tendon Crowell took a spot on the starting roster.

In the summer of 2006, he was named the starting strong side linebacker by Buffalo head coach Dick Jauron, replacing Jeff Posey.

Crowell started every game until suffering a late season injury against the San Diego Chargers.

Crowell underwent arm surgery after tearing his triceps muscle in the final game of the 2007 season.

An unrestricted free agent after the 2008 season, Crowell signed with the Tampa Bay Buccaneers on March 18, 2009.