If you look back on his 2011 season Ryan Mathews looked semi-productive. He finished the season as the number 9 fantasy running-back scoring 173 points, averaging 10.8 each game. On the surface he started very hot, averaging 16.2 ppg and starting every game before his week 6 bye. He cooled down after that, missing two games to injury in his final 11 and averaging an unspectacular 10.2 fantasy ppg in the remaining nine games he played.
So did he wear down playing his first NFL season as the featured back? Not exactly. Mathews' rushing numbers were constant before and after the bye: 17 attempts per game for 82.6 yards per game at a 4.85 average before the bye and 15.2 apg for 75.3 ypg at 4.95 ypc after the bye. We can ignore the attempts and yards per game considering in Week 10 against the Raiders Mathews had only 6 rushes for 34 yards, and that skews our per-game numbers a bit. But the yards per carry actually increased even though it was only a miniscule increase. But that tells us that he didn't wear down later in the season on account of a heavy workload. And we can count on Norv Turner (who is returning next season to San Diego) to run the ball nearly every first down and whenever it's third and short.
So what happened to make Mathews slow down enough to drop nearly 6 points per game? I believe San Diego's passing game. Mathews averaged (a respectable) 4 receptions per game before the bye, topping 50 yards receiving in four of those five games (and 60 in three). Fifty receiving ypg from one of your running-backs is great, if he played the whole season (healthy) at that level that is around 800 receiving yards. That puts him above ppr studs like LeSean McCoy and Ray Rice . The problem was after the bye. He averaged 3.3 receptions per game after the bye, which doesn't seem like much of a difference, but when he goes from 13 yards per reception (before bye) to 6.5 yards per reception (after bye) that makes a huge difference.
So what happened? Teams began to blitz Rivers more to make him force incorrect throws once they realized how "off" he was playing. (Norv) Turner was forced to use his running-backs to pass block more often and take away opportunities from them in the passing game. If the Chargers can come back next year with Rivers playing at the level he had always played at before this past year than Mathews should do great. Even if he doesn't as long as Mathews stays healthy he does well enough in the running game and is strong enough in the receiving game to be a top fantasy running-back.
He only scored 6 total touchdowns this year (all rushing) while Mike "the vulture" Tolbert scored 10 total times. Arguably the best news for Mathews so far this off-season is that the Chargers will let Mike Tolbert test free agency, though they still want to bring in a "bruiser" to backup Mathews. Still though, someone like Cadillac Williams (who the Chargers have their eyes on) or Michael Bush (who will probably end up on a team that can utilize him as more than just a backup) doesn't pose enough threat to warrant any concern about a time-share regarding Mathews next year.
So as the era of the "featured-back" comes to a close running-back committees are spreading like wildfire. Just remember come draft day that a healthy Ryan Mathews (in Norv Turner's system) has great odds to be a featured-back.