Kelley suffered a high ankle sprain and also sprained his left MCL in the first half of Sunday's home loss to the Minnesota Vikings. He had missed two other games and also parts of other contests because of various injuries this season. Kelley had only carried 62 times for 194 yards, with three touchdowns, for an average of 3.2 yards per carry.
The Redskins signed running back Byron Marshall off the Philadelphia Eagles' practice squad to take his place. Washington will use Samaje Perine as its primary back, with Chris Thompson remaining in his third-down role.
Compton suffered a Lisfranc sprain on Sunday. He had taken over for Mason Foster at inside linebacker; Foster's season ended last month because of a separated shoulder. Martrell Spaight will take over for Compton.
Washington will sign linebacker Zach Vigil to take Compton's spot on the roster, multiple sources told ESPN. The Redskins cut Vigil this summer.
The Redskins also have two other defensive starters on injured reserve: nose tackle Phil Taylor and lineman Jonathan Allen.