Detroit Lions running back Jahvid Best has been nursing his second concussion injury in three months, which he suffered last Sunday in the Lions first loss of the season to the 5-1 San Francisco 49ers.

It's possible now that the team can lose him -- and their running attack -- for the season. reported that Best has been advised by people close to him that he needs to strongly consider sitting out the year because of his concussion problems. He suffered his first concussion in August and missed one preseason game with the injury. He also had his college career at California cut short because of a concussion.

Anytime you talk about concussions, like we talked about before, it's not a situation you can tough out, Schwartz said. We've had some players that have had them, some guys that have missed time and some guys that have gotten back, and I think we'll just take that same approach with Jahvid. As soon as he gets clearance, he'll be back.

Offensive coordinator Scott Linehan said he certainly expects Best to return this year. Schwartz said it's not my area to recommend when asked under what circumstances he would suggest a player sit out the rest of the season.

That's the reason that the NFL has put people that know what they're doing in those things, he said. So like I said, it's not a situation where a player can will his way back, it's not a situation where a coach or anybody else can put a player back before the independent doctors say he's able to be able to do those things.

Maurice Morris is the Lions' likely starter at running back Sunday against the Atlanta Falcons. Morris said he hasn't seen Best all week, even in meetings.

They kind of want him to stay away from the noise and lights, especially around here, said Morris.

Other players said Thursday that they do not expect Best to play Sunday.

Keiland Williams is the only other healthy running back on the Lions' 53-man roster, though the team worked out two running backs Thursday, including former Eagle Eldra Buckley.

Running back James Davis, who was signed to the practice squad on Wednesday, went on practice squad injured reserve today.

Linebacker Justin Durant and tight end Tony Scheffler, both coming back from concussions, returned to practice today for the Lions, as did defensive end Kyle Vanden Bosch, cornerbacks Chris Houston and Aaron Berry and safeties Amari Spievey and Vince Fuller.

Receiver Rashied Davis (foot) remains out for the Lions, but was not wearing the walking boot he had on during practice Wednesday.

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