Best has been symptom-free for months following his most recent concussion last October, but is nonetheless on the physically unable to perform list at Lions training camp, which began last week.
From the Free Press:
"Everything was trending toward him being ready to go the first day of training camp," Mayhew said before practice today. "It didn't happen that way, so you have to kind of adjust. We have adjusted our expectation on that."
Mayhew said the Lions aren't at a point yet where they need to make a move to protect themselves at the running back position but will "be ready to pull the trigger" when the time comes.
"I guess there is that point," Mayhew said. "I think right now it's very early in the game to start making that kind of call. It's up to the medical professionals to decide when he's going to be available. Eventually he will get cleared. I'm very positive. I feel very comfortable saying that. It's just a question of the timing of it is up to those guys."
Even if Best is not suffering the ill effects of his most recent concussion, the third-year back does has a checkered history with head injuries. Last season he suffered a concussion in the preseason and then another in mid-October. He also had a rather horrifying concussion as a running back at Cal.
Lions running back Mikel Leshoure, who is coming off an Achilles injury that prevented him from playing in 2011, has been slowed by a hamstring injury. As a result, Kevin Smith and Stefan Logan, who has 24 careers in three NFL seasons, have been taking the majority of the reps at running back during training camp.