Thomas is attempting his third comeback from an injury to the ACL in his right knee. The cornerback had a $6 million option in his contract in March, and the Giants were going to avoid that option after Thomas re-injured his ACL during training camp last year.
But the two sides have worked out a new one-year deal for 2013, and Thomas tweeted a picture of his helmet on Monday asking to guess who's back.
"I'm blessed and happy to have another opportunity to play football, especially with such a loyal organization, the one I started my career with," Thomas said in a statement released by the Giants. "For them to give me another opportunity to prove myself, I feel very blessed."
"My knee feels great," Thomas added. "It was a little struggle at first. It was a little inconsistent with the swelling. But for the last month-and-a half I haven't dealt with any swelling at all. It's progressed the last two weeks since I started running. The doctors are really happy with the way I'm progressing. They had to increase my workload because it wasn't enough."
Thomas was slated to start opposite Corey Webster in training camp last season as he was returning from a torn ACL suffered during the 2011 preseason. But he suffered another setback that required surgery.
Shortly after this past season ended, Giants general manager Jerry Reese said the 28-year-old Thomas might be best served switching to safety, citing that the position change might help with his knee and prolong his career.
"At this point, I don't care if they move me to kicker," Thomas said. "I just want to play football."
Thomas last played in a regular-season game in the final game of the 2010 season on Jan. 2, 2011. He missed all of 2011 and 2012 with right ACL tears.
Thomas, who first tore his right ACL while at USC, recently began jogging outside a pool earlier this month.
"It's been a long two years," Thomas said. "It's definitely been a test of my will. But it's made me a stronger person. It showed me a lot of things about myself that I needed to fix and at the same time it showed me how strong I was. It's been a tough time for me and my family and especially beating myself up."