Ashburn, VA -- (Sports Network) - Washington Redskins running back Clinton Portis was limited in practice on Friday, and is listed as questionable for Sunday's matchup with the Seattle Seahawks.

The seventh-year pro has been dealing with a knee sprain he incurred during the Redskins' 23-6 home loss to Pittsburgh on November 3. On Friday, Redskins head coach Jim Zorn termed Portis as being a game-time decision after sitting out practice Wednesday and Thursday.

Portis was questionable leading up to last Sunday's 14-10 loss to Dallas but suited up and gained 68 yards on 15 carries.

Backup Ladell Betts, who is also dealing with a knee injury, returned to action after missing the team's previous three contests but was limited to just one carry for one yard against the Cowboys.

Portis is the second-leading rusher in the NFL this season with 1,063 yards. Only Minnesota's Adrian Peterson (1,100) has more. Portis has also rushed for seven touchdowns, and caught 20 passes for 156 yards.