RB Ryan Mathews may have been the Chargers' first-round pick this year, but he's not the only guy they trust in the backfield. Mike Tolbert signed with the Bolts as an undrafted free agent in 2008, and he spent most of his rookie season as a fullback. But from what we hear, the team learned during '09 and the preseason that Tolbert can be very effective as a running back, and it plans to get him involved more in 2010. Replacing an injured Mathews in Week Two, the Coastal Carolina product rolled over the Jaguars for 82 yards and two touchdowns on 16 carries, and San Diego isn't worried about having to start him if the rookie can't play Sunday. Even when Mathews is healthy, the 5-9, 243-pound Tolbert is expected to be the Chargers' primary goal-line option, as his bulldozer running style is difficult to stop in short yardage. Add Darren Sproles into the mix, and the Bolts feel like they have their backfield bases covered.