ALLEN PARK, Mich. (AP) — Tatum Bell walked off the practice field, wearing a Honolulu blue jersey and holding a silver helmet.

The running back would’ve wagered his house, car and clothes there was no chance of that happening this season.

‘‘I would’ve bet everything I had that I wouldn’t be a Detroit Lion this year,’’ Bell said Thursday after the opening day of training camp. ‘‘I know for a fact if Mike Martz was here, I wouldn’t be here.’’

The Lions and Martz parted ways during the offseason, and the pass-happy offensive coordinator was hired by the San Francisco 49ers.

After running for nearly 2,000 yards and scoring 10 times over two seasons in Denver, Bell had a solid Detroit debut under Martz with 87 yards rushing and a touchdown in a win over the Oakland Raiders.

He started the next four games before being benched for the rest of the season, losing his job and carries to Kevin Jones and T.J. Duckett, both of whom are ex-Lions.