With Rookies being an unknown and LeShoure having the type of injury where players don't always recover from and Kevin Smith being the same Kevin Smith the Lions flat out gave up on (and nobody else wanted), I think I keep Best. I agree you're gambling but that's what separates the FF Beasts from the Leasts; the gambles that pay off. And Best was a SOLID top 6-8 RB in PPR this year. The coach has been on record saying they were just being very cautious because of the concussion and Best's age, etc. I never heard anywhere that this concussion was significantly Bad or anything.
So in the end we know he is on a team that can score and he has unique talent and can get it done. I look at Sproles and think, on that team, he could easily be THAT guy. I also look at a guy in the NHL that has sat out almost a year due to concussions and while I see the "gamble", I also see that when you have a talented player, you don't just dump them. Kevin Smith came in and impressed but he IS the same guy that was flat out released by the team and had no suitors from the rest of the league. We see guys come in when they are fresh and everyone else is beat up and look great for very short periods. I don't think the Lions are that Sold on Smith. If they believed in him that much, they would not have cut him the first time. So, I will gamble on Best and hope he becomes an Isaac Bruce or Fred Taylor; a guy that was snake bitten early but then had several good years once he got completely healed up. I think the upside to keep him is more than anything someone would give for him.