BOSTON (CBS) — When Stevan Ridley went down during the Patriots’ win in Buffalo on Sunday afternoon, it did not look good for the running back. And after the game, the Patriots were still reportedly fearing the worst.

According to NFL Network’s Albert Breer, Ridley will undergo an MRI on Monday.

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“Fear is that he tore his ACL,” Breer wrote.

The Boston Herald’s Jeff Howe also reported on Ridley, noting that the “damage/severity [is] not known.”

Ridley suffered the injury late in the third quarter of the Patriots’ 37-22 win. He took a handoff from Tom Brady and ran to the left side when Buffalo safety Stephon Gilmore made a diving tackle attempt. Gilmore’s helmet appeared to contact Ridley’s leg, and the running back spun through the air before hitting the turf.

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Ridley remained down on the field in great pain, and the TV cameras later showed him distraught on the Patriots bench.

The fourth-year running back has 340 rushing yards and two touchdowns on 94 carries this season. He entered Sunday’s game on pace to top 1,000 yards for the second time in his career.

Shane Vereen has the second-most rushes on the team with 42. If Ridley is lost for the season, the Patriots have rookie running back James White on the roster. White, a fourth-round pick out of Wisconsin, has seen action in just one game this year, gaining 21 yards on three rushes against Kansas City.

Linebacker Jerod Mayo, the team leader in tackles, also left Sunday’s game with an injury. Mayo was carted off the field in the first half, and he left the stadium on crutches, according to Howe.

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