But on April 4, 1979 he Carlson suffered a serious back injury that required spinal fusion at the Mayo Clinic. He was out of the league for a year and a half, returning November 7, 1980. He played two years with the Blues from 1982-84, but his career was not quite done yet. Unhappy as an airfreight salesman and playing shinny twice a week in Minnesota, he came out of retirement in November 1986, some thirty months after having last played. Eight games later, he was done for good.

Jack missed his big acting break in 1974-75. While playing for Johnstown, the movie Slap Shot was being made. Jack's two brothers, Jeff and Steve, were stars of the flick, and Jack was supposed to be the third brother, all of whom were terrorizing the league with their hits and fights. But when he was recalled by the Minnesota Fighting Saints just prior to filming, his part had to be given to Dave Hanson.