Hankerson suffered the injury in Sunday's 20-9 loss to Miami.
Drafted by the Redskins in the third round last April, Hankerson has started the last two games and caught a team-high eight balls for 106 yards on Sunday.
The Miami-Florida product had 13 receptions for 163 yards in four games played this season.
It will be Moss' third consecutive game missed since suffering a Week 7 hand injury that required surgery.
Shanahan did say that Moss has a chance to play the following week at Seattle.
The 11-year pro has 25 receptions for 301 yards and two scores in six games this year.