Thomas, 25, was signed to the franchise amid wide receiver Johnny Knox' expected status on the Physically-Unable-to-Perform list following spinal fusion surgery in December, the Chicago Tribune reported Thursday.
"I know I'm joining an organization that's legendary. That's the first thing that comes to mind, the tradition and the history," Thomas said on the team's Web site. "The team has shown so much promise and just needs a little bit more to get to the Super Bowl. I think they're putting the right pieces together. They have the right mentality to be right there. I'm looking forward to joining the team and adding to the success of the team.''