Vikings kicker Blair Walsh left today's practice early after feeling a "little bit of a twinge" in his left hamstring after a kickoff, coach Leslie Frazier said after practice.

"We just shut him down," Frazier said. "Precautionary. So we'll see how he feels tomorrow.

"I think he'll be fine, based on what [head athletic trainer] Eric Sugarman said. He should be fine. Just want to be smart."

Frazier said the team, obviously, does have a short list of kickers it can call in an emergency.

"We don't want to get to it," Frazier said. "I think he'll be fine. ... All indications are he will be."

Running back Adrian Peterson (personal reasons) and receiver Joe Webb (illness) missed practice Thursday. Peterson will be back Friday. As for Webb, Frazier said, "Joe had an illness, a virus, so hopefully he'll be back tomorrow."

Frazier said cornerback Chris Cook (groin) and strong safety Jamarca Sanford (hamstring) are expected to play Sunday after missing the last game against Pittsburgh. Cook was limited in practice today while Sanford had full participation.

Also limited in practice were QB Christian Ponder (rib), TE Rhett Ellison (knee) and DT Kevin Williams (knee). Ponder has been told he's been cleared to play. Matt Cassel is expected to start, although Frazier said he won't reveal his quarterback decision until Friday. Chip has a post coming shortly on the QB situation.