The 29-year-old Ross stepped up after the season-ending injury to the Giants' recently-signed Terrell Thomas and intercepted a career-best four passes in 2011.
He started 15 games last season in place of Thomas and had a career-high 60 tackles. He was the Giants' first-round pick in 2007, and he started 24 of his first 30 games with the Giants before playing in just four games in 2009 due to a hamstring injury.
The Giants were expected to lose Ross in free agency, as they have been trying to re-sign some other veteran free agents while saving money to pay young stars such as Victor Cruz down the road.
Ross was the Giants' third cornerback on the depth chart behind Corey Webster and Thomas in 2010. The Giants have lost two starters from Super Bowl XLVI in the past couple of days, as Ross' departure comes days after free agent wide receiver Mario Manningham opted to join the San Francisco 49ers.
The Giants, though, have Webster and Thomas returning as the projected starters with last year's first-round pick, Prince Amukamara, expected to become the third cornerback. They also re-signed Bruce Johnson, Michael Coe and Justin Tryon for depth in the secondary.
Information from ESPN NFL Insider Adam Schefter, ESPNNewYork.com's Ohm Youngmisuk and The Associated Press was used in this report.