Bruce Tollner, Cantwell's agent, says his client has been released.
The move comes as the Panthers must cut 22 players Saturday to reach the 53-man regular-season limit.
The 6-foot-6 Pike was Carolina's sixth-round pick out of Cincinnati. After throwing just one pass in the first three preseason games, he was 10 of 18 for 44 yards while playing the entire second half against Pittsburgh Thursday.
Cantwell went undrafted last year out of Louisville and spent most of last season on Carolina's practice squad. He was 6 of 9 for 36 yards against the Steelers.