James White was carted off in the second quarter Sunday at Gillette Stadium.
The 29-year-old running back and team captain underwent further tests on Monday and is “out indefinitely,” Rapoport said.
White had been carted off the field in the second quarter at Gillette Stadium after rushing for six yards and a first down. In his absence behind starter Damien Harris, Brandon Bolden and J.J. Taylor stepped into the offense to play 33 snaps and 10 snaps against the Saints, respectively.
Patriots rookie running back Rhamondre Stevenson, drafted No. 120 out of Oklahoma, had been inactive for a second consecutive week.
White totaled 12 catches for 94 yards to go with nine carries for 32 yards and a touchdown through two games this season. The 2014 fourth-round pick from Wisconsin had re-signed on a one-year deal worth $2.462 million in March.
New England hosts the Tampa Bay Buccaneers for an 8:20 p.m. ET kickoff next Sunday.