Ian Rapoport of NFL Network reported Shepard will undergo an MRI on Monday.
Shepard went down in Sunday's loss to the Chicago Bears. He had two receptions for 29 yards before exiting.
In his fifth NFL season, Shepard missed six games due to injury last season and missed five more in 2017. He's compiled eight receptions for 76 yards on the season through two games.
The Giants offense is already without Saquon Barkley, who will miss the rest of the season with a torn ACL. Golden Tate and Darius Slayton will have to step up and take a more significant share of the targets with Shepard out of the lineup.
Tate led all Giants receivers with five catches for 47 yards against the Bears.