The Giants also announced that they had signed quarterback Rhett Bomar and safety Sha'reff Rashad from the practice squad.
The signing of Bomar and Rashad will allow the Giants to keep Bomar and Rashad under contract. They would have become free agents after the season.
Jacobs will have arthroscopic surgery on his right knee next week. He played in 15 games and leads the team with 835 yards rushing.
Ross missed the first nine games with an injury to his left hamstring. He returned to play four games before reinjuring the hamstring.
Bomar was the Giants' fifth-round draft choice in 2009, from Sam Houston State. He completed 4 of 9 passes in the preseason.
Rashad was signed as a free agent on May 8. He was waived on Sept. 5 and signed two days later to the practice squad.
The Giants filled the open practice squad spots by signing offensive lineman Rueben Riley and receiver Bruce Francis.
Copyright 2009 by The Associated Press