ALLEN PARK -- While the Lions seemed to be headed in the right direction under GM Martin Mayhew and coach Jim Schwartz, they have much work to do.

Depth was a huge issue last season for the 2-14 team. Some of that has been addressed, but depth will still be a problem this season. The reason is simple. The Lions have no players on the roster who were drafted by the Lions between 2002 and 2006, thanks to Matt Millen.

Depth became an issue over the weekend when backup linebacker Jordon Dizon, who was starting in place of the injured DeAndre Levy, went down with a knee injury and is expected to be lost for the season.

The Lions signed undrafted free agent LB Lee Campbell on Monday. Campbell, who played at Minnesota, had been in minicamp with the Lions in June. He was released on July 31.

(Follow me on Twitter @paulapasche.)