ESPN.com reported Sunday that Mosley was found with marijuana after the team switched hotels while in London for last week's game against the Atlanta Falcons at Wembley Stadium. Hotel security inspected Mosley's room after a smoke alarm was disconnected, the report says.
Mosley, who was sent home the day before the game, and the NFL Players Union have reportedly filed a grievance challenging the suspension and lost pay.
The 6-foot-2, 314-pound Mosley has recorded seven tackles and 2.5 sacks this season to help the Lions maintain the second-best rush defense (3.3 ypc) in the league. Mosley's reinstatement comes after starter Nick Fairley injured his knee against the Falcons. Caldwell said Monday that he did not know when Fairley would return.
Caldwell also said Monday that rookie linebacker Kyle Van Noy has been activated from the short-term injured reserve list. Van Noy, a second-round pick out of BYU, missed the first eight games of the season while recovering from a hernia suffered in September.
The Lions (6-2, 1st place NFC North) were idle last weekend and host the Miami Dolphins on Sunday.
- Chris Johnson