Safety Eddie Jackson on Saturday was downgraded from doubtful to out and did not travel with the Bears to Kansas City for Sunday's game against the Chiefs.
Jackson sat out practice all week with a foot injury that caused him to exit last weekend's contest versus the Buccaneers in the second half.
Hardy was selected by the Rams in the seventh round of the 2022 draft out of Montana State. He appeared in six games as a rookie last year, primarily on special teams. Hardy was waived by the Rams as part of final cuts Aug. 29 and signed to the Bears' practice squad two days later.
Thomas signed with the Bears last year as an undrafted free agent from Western Michigan. He appeared in five games as a rookie in 2022, playing 13 snaps on defense and 66 on special teams.
In addition, linebacker Khalid Kareem was placed on injured reserve with a hip injury. Kareem was a healthy scratch in the first two games this season.