Cowser signed with the Oakland Raiders after going undrafted in the 2016 NFL draft. On September 3, 2016, he was waived/injured by the Raiders and placed on injured reserve.[2] On September 10, he was released from the Raiders' injured reserve.[3] He was signed to the practice squad on October 4, 2016.[4] He was promoted to the active roster on November 26, 2016.[5]
On September 1, 2018, Cowser was waived by the Raiders.[6] He was re-signed to the practice squad on October 22, 2018.[7] He was promoted to the active roster on October 30, 2018.[8] He was waived on November 5, 2018, and was re-signed to the practice squad.[9] He was waived on November 13, 2018, and later re-signed to the practice squad.[10][11]
Cowser signed a reserve/future contract with the Raiders on January 1, 2019.[12] He was waived during final roster cuts on August 30, 2019.[13]
Coaching career
In the spring of 2021, Cowser joined Weber State as a defensive assistant under head coach Jay Hill.[14] Cowser was promoted to a full-time position of defensive ends coach for the 2022 season.[15] Following Hill's departure, Cowser joined Utah Tech as the defensive line coach and tight ends coach under head coach Paul Peterson.[16] Following Peterson's firing, Cowser returned to Weber State, again as the defensive ends coach, this time under head coach Mickey Mental.[17]