Report: Lions' Caldwell only signed through 2018 season

Detroit Lions head coach Jim Caldwell signed a contract extension in the offseason, the details of which weren't revealed at the time.

It turns out, Caldwell was only extended through the 2018 season, with an option for the following year, NFL Network's Ian Rapoport reports.

Caldwell has operated on short-term deals for the majority of his four-year tenure in Detroit.

He's led the Lions to the playoffs in two of his four seasons and has the club at 6-6 and in playoff contention again this year.