Vikings coach Leslie Frazier said injured running backs Adrian Peterson (foot sprain) and Toby Gerhart (hamstring) will not practice today and probably won't practice until Friday, if at all. He also said he's more hopeful that Gerhart will be able to practice on Friday than Peterson.

Frazier said Peterson already has assured him that he'll be ready to play, but added that the team will "err on the side of caution," keeping in mind Peterson's long-term value and the fact that the team is mathematically eliminated from the playoff picture at 3-9-1. Frazier also said Peterson would have to practice on Friday before the team would play him in the game on Sunday.

Meanwhile, Frazier officially announced Matt Cassel as the starting quarterback for Sunday's game against the Eagles at Mall of America Field. It will be Cassel's fourth start of the season and second straight start. It will be the first time he's started after losing a start the previous week. But his turnover-free effort in the wild 29-26 loss at Baltimore on Sunday was enough to earn a second straight starting opportunity. Cassel is 1-2 as a starter, but did play the second half of the comeback win over the Bears two weeks ago.

Christian Ponder, who has been cleared from the concussion that sidelined him last week, will serve as the backup. Josh Freeman will be the No. 3 QB.

In other news, tight end John Carlson still has not passed the concussion protocol and cannot practice until he does.

Cornerback Xavier Rhodes (ankle) and guard Brandon Fusco (knee) are day-to-day, Frazier said.

Here is the updated practice/injury report:

Vikings: TE John Carlson (concussion), RB Adrian Peterson (foot), RB Toby Gerhart (hamstring), G Brandon Fusco (knee), CB Xavier Rhodes (ankle) and CB Josh Robinson (chest) did not practice. LB Larry Dean (knee) was limited. LB Chad Greenway (wrist) was a full participant.

Eagles: LB Najee Goode (hamstring) did not practice. S Earl Wolff (knee) was limited. CB Brandon Boykin (hip) was a full participant.