Knett joined the Isfahan-based club in September 2021 from Greek football team Panetolikos.
The 31-year-old goalie signed for Sepahan as a replacement for Payam Niazmand but failed to meet the expectations.
“I want to thank you for everything. I was allowed to play for this great club and get to know a lot of great people. I’m very grateful for the way you welcomed my family and me, we felt very comfortable,” Knett posted on his Instagram account.