The move isn't surprising considering Thomas' history of injury problems.
The Colts signed Thomas, 29, to a four-year, $14 million contract in 2013 with the hopes that he would bring stability to their offensive line.
That never happened. He tore his right quad and left biceps in Week 2 in 2013, causing him to miss the rest of the season. Thomas' 2014 season ended before it even started when he tore the same quad in training camp.
Indianapolis just took Thomas off of the physically unable to perform list on Friday.
Can Colts protect Luck after Thomas cut?
Despite the release of guard Donald Thomas, ESPN NFL Insider Field Yates doesn't think the Colts will struggle to protect Andrew Luck this season.