The New York Giants placed linebacker Keenan Robinson on injured reserve on Tuesday and signed linebacker Akeem Ayers and offensive guard John Greco, the team announced.
Robinson, 28, recorded 32 combined tackles and two passes defensed in six games this season before he suffered a season-ending quad injury in New York's game against the Los Angeles Rams on Nov. 5.
Ayers, 28, recorded one interception, two sacks, two passes defensed and 12 tackles in 16 games with the Indianapolis Colts last season. A six-year veteran, he has not appeared in any games in 2017.
Greco, 32, did not appear in a game with the New Orleans Saints this season. He played in 111 games with the St. Louis Rams and Cleveland Browns from 2008 to 2016.
New York also waived defensive end Devin Taylor, who recorded one combined tackle in two games with the Giants this season.