Buffalo Bills running back Fred Jackson could miss up to a month after suffering a groin injury and fellow running back C.J. Spiller is scheduled to have surgery on a broken collarbone.

Buffalo’s top two running backs were carted off the field in the first half of Sunday’s 17-16 win over the Minnesota Vikings.

Jackson injured his groin on the final play of the first quarter and Spiller injured his left collarbone at the end of a 53-yard run in the second quarter.

Jackson said his injury will not require surgery after doctors gave him that prognosis.

“It’s not as bad as it could have been,” Jackson told WGR 550 in Buffalo on Monday. “It’s typically a four-week injury. But we’ll try to do some things to get it sped up.

“I like to think of myself as somebody who can come back before typical. It’s just gonna be on me to get in there and rehab and see the team doctors and do what it is they want me to do.”

According to ESPN sources, Spiller will have surgery Monday.

Spiller is in the final year of his rookie contract, meaning his last play with the team might have been Sunday’s 53-yard burst that ended in injury.