MINNEAPOLIS -- Minnesota Vikings star running back Adrian Peterson sprained his left ankle at the end the first quarter of Sunday's 27-21 loss to Oakland, and he didn't return.

X-rays showed no breaks, coach Leslie Frazier said afterward, and Peterson was still in his shoulder pads on the sideline during the second half. He will have an MRI to make sure there's no more damage. Peterson said he hoped to play next Sunday at Atlanta.

Peterson hobbled off the field after a tough 12-yard run through heavy traffic. His left ankle rolled hard as he was brought down by the Raiders, and he could barely put weight on it as he was helped to the sideline by team trainers. Peterson grimaced on the table while his ankle was looked at and rode on a cart to the locker room for further examination.

Peterson entered the week fifth in the NFL in rushing with 846 yards. He scored his 11th touchdown rushing before he got hurt and finished with 26 yards on six carries.