He is expected to miss about a month, as reported by WBZ-TV in Boston.
Mayo needed attention on the field before being aided off the field by two trainers. He was unable to walk off the field with his teammates at halftime and was instead carted from the field.
"We'll look at it tomorrow and see where he's at going into this week," Patriots coach Bill Belichick said following the game.
Also, Patriots running back Danny Woodhead appeared to suffer a left ankle injury late in the first half. He did not return.
Woodhead hobbled to the sideline and was trying to walk off the injury before the intermission.
In other injury news, Patriots defensive lineman Kyle Love suffered a right ankle injury in the first quarter of Sunday's game against the Raiders.
Love needed attention from the trainers before gingerly walking off the field on his own power. He soon returned to the locker room for examination, but was back on field for the first defensive series of the second half.
Thin already on depth on the line, the short loss of Love pushed veteran Gerard Warren -- re-signed earlier this week -- onto the field at defensive tackle.
Chris Forsberg is a columnist and reporter for ESPNBoston.com.