Lions coach Jim Caldwell has yet to clarify why he sent C.J. Mosley home from London on the eve of Detroit's game against the Falcons, but sources told ESPN that after the team moved from its serene countryside hotel to a downtown London hotel near Hyde Park, a disconnected smoke alarm alerted the hotel security staff to check the defensive tackle's room.
Mosley was discovered with marijuana, sources said, and the Lions suspended him for two weeks for conduct detrimental to the club.
The team had no comment.
Inasmuch as the incident would fall under the league's substance abuse policy, there is a question about whether the team can dock him two weeks' pay unless they can cite another incident.
Mosley and the union have filed a grievance to contest the suspension and docked pay.
On Tuesday, Caldwell would not clarify whether Mosley's two-week suspension meant two games or two weeks -- essentially whether or not he would be available for Week 10 against Miami.
"I think the statement stands on its own," Caldwell said. "If you take a look at it, read through it and kind of glean from it what you'd like. But we said two weeks and in two weeks, he'll return."
Mosley was suspended and sent home from London the day before the Lions faced the Falcons in Week 8, so if two weeks is taken to the letter, Mosley would be eligible to return the day before Detroit's game against Miami.
ESPN.com's Michael Rothstein contributed to this report.