The Giants placed Casillas (neck) on injured reserve Wednesday, Art Stapleton of The Bergen Record reports.
Casillas' neck stinger worsened during the Giants' Thanksgiving Day loss to the Redskins, then sidelined him for the Week 13 loss to the Raiders. With Casillas evidently not making much notable progress in recent days, the Giants decided to shut the linebacker down for the season. He'll finish the 2017 campaign with 35 tackles (25 solo) and one pass breakup across eight contests. Casillas will become a free agent this offseason and may have played his last game with the Giants.