He also had stints in the NFL with the New York Giants, Minnesota Vikings and Chicago Bears, but saw no playing time with them.
Mestnik additionally spent a year with the Newark Bears of the Continental Football League (COFL).
[3] Mestnik began attending Marquette University in 1956 but did not play for their football team until his sophomore year in 1957.
[4] He quickly became a starter at fullback and was one of the top players for the team that went 0–10 and ranked 110th out of 112th major colleges.
[9][10] For his performance, he was selected Marquette's most valuable player and was given the Alpha Kappa Memorial Trophy.
[18] After being released by the Cardinals, Mestnik spent time with the taxi squad of the New York Giants in the 1962 season.
[19] While out of football in the 1963 offseason, Mestnik worked as a sales engineer trainee at Reliance Electric and co-managed a driving range with his uncle Hank, a former minor league baseball player, and Joe Sedely, a boxer.
[12] He then signed with the Green Bay Packers for the 1963 season but was released at the start of September during roster cuts.
[21] He appeared in 11 games for the Packers in the 1963 season and ran the ball once for four yards, additionally returning one kickoff for no gain.