Dalton, who was the team's starter to begin the season, will likely get the start on Thursday against the host Detroit Lions, NFL Network Insider Ian Rapoport reported Monday night.
Head coach Matt Nagy confirmed that Dalton will start when talking to the media Tuesday.
On Sunday, Dalton came on in relief of Fields and completed 11 of 23 passes for 201 yards, two touchdowns and no interceptions. It was Dalton's first game action since Week 5 and Thursday will be his first start since Week 2. A three-time Pro Bowler with the Cincinnati Bengals, Dalton signed with Chicago in the offseason on a one-year pact. The Bears are 1-1 with Dalton as a starter and 2-2 in games he's appeared in.
While initial reports of Fields having bruised ribs indicate the rookie avoided a major injury, the short week points to Dalton being a safer play for the squad.
Fields spent Monday undergoing further testing on his ribs and the turnaround was just too quick, Rapoport noted.
In four games this season, Dalton has completed 48 of 73 passes (65.8%) for 471 yards, three touchdowns and one interception.
The 34-year-old Dalton will be starting on Thanksgiving for just the second time in his 11-year career, but it will be the second straight year he's played on Turkey Day, as he was the starter for the Dallas Cowboys in a loss last season against the Washington Football Team.
The Bears (3-7) are aiming to end a five-game losing streak when they face the Lions (0-9-1), the last winless team in the NFL landscape. Chicago defeated Detroit, 24-14, in Week 4 with Fields starting and has won six of the last seven in the rivalry.