Redskins beat writer John Keim on the team's backfield split:
Last season Alfred Morris took 66 percent of the Redskins' 401 carries. And in his first three seasons with Washington, Morris took 64 percent. That's a good number for him, and if he's running well then I'd expect that to continue. I think the other part is that we don't know how well Matt Jones will run the ball in the NFL. If he's running well, then I could see him getting a handful of carries per game. Regardless, he'll have a role as a third-down back. Also, if the Redskins are as committed to the run as they say, then they should have at least 50 more carries than last season's total of 401. That won't change the percentage, but it would mean more chances for both. Another factor is how often they use the zone-read option. If it's less of a factor, then that's more carries for Morris/Jones to split.
Morris should continue to be a fringe RB1 in standard formats and a solid RB2 in PPR leagues. It sounds like Jones will take over the role vacated by Roy Helu.