Jerod Mayo suffers knee injury

ORCHARD PARK, N.Y. -- New England Patriots linebacker Jerod Mayo was carted off the field with a knee injury in the second quarter of Sunday's game against the Buffalo Bills, and his return has been ruled out by the team.

Mayo, a captain and signal-caller on defense, was immediately surrounded by teammates after a Boobie Dixon run up the middle on first down, as he wound up on the bottom of the pile. Patriots coach Bill Belichick also came over from the sideline, reflecting the initial reaction that the injury was serious.

Several Patriots and Bills players came over to the cart as Mayo was helped on, with Patriots veteran Vince Wilfork bringing Mayo's head into his own chest and kissing him on top of the head.

The Patriots are already thin at linebacker, with starter Dont'a Hightower not playing with a left knee injury. That has thrust undrafted rookie Deontae Skinner and special teamer Chris White into the team's base defense.

This would mark the second straight season that Mayo's season was affected by a serious injury, as he was lost to a torn pectoral muscle Oct. 13, 2013 against the New Orleans Saints.

Running back Stevan Ridley (knee) was ruled out in the third quarter and guard Dan Connolly left in the second quarter with a head injury and was later downgraded to out.