Surgery will not be required on the sprained right foot of Vikings running back Adrian Peterson, although he will remain in a walking boot this week, leaving in doubt his status for Sunday's game against the Philadelphia Eagles at the Metrodome, a team official confirmed Tuesday.

An MRI and a CT scan revealed no fractures or structural damage, and Peterson said Monday he expected to play. But a team official, who spoke on condition of anonymity, said it was too early to decide.

X-rays at M&T Bank Stadium in Baltimore were negative after Peterson left during Sunday's 29-26 loss to the Ravens early in the second quarter. He "felt it pop a couple times," he said, when his foot twisted underneath Ravens linebacker Arthur Brown's tackle near the Vikings' bench.

After being carted to the locker room, Peterson kept his pads on and tried to stay loose during the third quarter before determining he could not push off or run effectively on the snowy turf.

"It really didn't swell up too much, so that's another positive thing," he said Monday. "But I'm sure it will be sore for a little bit."

Meanwhile, backup running back Toby Gerhart strained his hamstring in his 41-yard touchdown run with 1:27 remaining.