Zylstra was released by the Panthers on Tuesday, Joe Person of The Athletic reports.
Zylstra re-signed with the Panthers in March, but he will hit the open market after failing to make the team's final roster. The wide receiver played 13 games with the Panthers in 2021, catching 18 passes for 250 yards and a touchdown. The 29-year-old will likely sign with another squad in need of wide receiver depth.