With Rob Kelley a long shot to play vs. Niners, Samaje Perine takes over

ASHBURN, Virginia – The Washington Redskins offense probably will be without their starting running back -- and possibly their Pro Bowl left tackle -- for Sunday’s game vs. the San Francisco 49ers.

Redskins coach Jay Gruden called Rob Kelley a “long shot” to play vs. the 49ers because of a sprained ankle. Also, left tackle Trent Williams did not practice Wednesday because of a knee injury, though Gruden said he might be able to play. They’re also expecting to be without corner Josh Norman, who has a fractured rib and did not practice.

Linebacker Zach Brown missed a second practice this week because of an illness. Gruden said he expects him to be ready for Sunday.

Williams’ absence would be big because the Redskins already are without backup tackle Ty Nsekhe, who is out because of a core muscle injury. Gruden said he’s hoping Williams is able to at least be limited in practice Thursday. But Gruden will have a better idea on his status Friday or Saturday.

As for Kelley, barring a major turnaround, he’ll be replaced by rookie Samaje Perine. Chris Thompson will remain the third-down back with Mack Brown serving as Perine’s backup.

In some ways using Perine alters how Washington has success running the ball.

Perine has started to run better out of shotgun formation; Kelley is best when the quarterback is under center. This season, with the quarterback under center Perine has carried 30 times for 64 yards, according to ESPN Stats & Information. When Kirk Cousins is in shotgun, Perine has 16 carries for 79 yards.

Kelley, meanwhile, is more consistent with 24 carries for 124 yards with Cousins under center. He has carried five times for seven yards out of shotgun, but last season he averaged 4.08 yards out of that look.

For Perine, it’s a matter of getting used to it -- he mostly ran out of shotgun looks in college. It’s a matter of patience and allowing blocks to set up. He showed more of that patience in the second half vs. Kansas City. On three of his last four carries he ran the ball when Cousins was under center and gained 12 yards. The line blocked well, giving him a better chance to find a hole.

Gruden said he didn’t realize the stats played out this way for Perine, but he also knows his rookie back needs to run with more patience.

“Samaje is a power runner and he should be good under center or in shotgun,” Gruden said. “Maybe some runs under center, some outside zones, he’s still feeling his way through those cuts and staying on course. That happens to a lot of young backs. A lot of them are so anxious to get the cutback to the hole, they don’t read them out all the way. ... Under center, he has to be more patient with his reads.”