In the NFL, Westerman has been a member of the Miami Dolphins, Arizona Cardinals, Indianapolis Colts, Buffalo Bills, Pittsburgh Steelers and Cleveland Browns.

Following his freshman season, he moved, this time to Brampton, Ontario, and enrolled at Notre Dame Secondary School.

[2] Westerman received three scholarship offers from National Collegiate Athletic Association (NCAA) colleges before accepting one from Rutgers.

After redshirting in 2004, Westerman made a quick impression on the Rutgers coaching staff after recording six tackles in two games to begin 2005.

[11] Westerman was named second–team All–Big East following the season along with teammates Brian Leonard, Cameron Stephenson, Pedro Sosa, Jeremy Ito, Ramel Meekins, Devraun Thompson, Ron Girault and Courtney Greene.

[12] During spring practice, Westerman and two other starter defensive linemen missed the annual intersquad scrimmage due to injuries.

"[18] Beginning in March 2008, Rutgers attempted to convert Westerman to defensive tackle,[19] so he could replace the departed Eric Foster.

[22] Westerman suffered a torn biceps against Louisville and was forced to sit out the rest of the season which included a bowl game.

[25] On June 9, 2009, Jets head coach Rex Ryan said that he expected Westerman to make the team's final roster.

[26][27] He ended up making the final roster as an outside linebacker[28] and recorded two tackles and a sack in his debut against the Houston Texans on September 13.

[29] On October 9, 2011, Westerman recorded 5 tackles along with 2 sacks against the New England Patriots but in a losing effort while the Jets lost 30–21.

[34] Unfortunately for Westerman, Ottawa Redblacks receiver Brad Sinopoli would end up winning the award for Most Outstanding Canadian.

[37] Westerman played in eight regular season games for the Ti-Cats, registering 10 tackles before being placed on the 6-game injured list on September 28, 2018, with an Achilles tendon rupture.