Thompson is viewed as a reliever and is not part of the competition for the Cubs' final rotation spot, Jordan Bastian of MLB.com reports.
Kyle Hendricks' shoulder injury will open up a starting role to begin the year, but Thompson isn't a candidate to fill it. Hayden Wesneski, Javier Assad and Adrian Sampson are the frontrunners. Thompson made 17 starts and 12 relief appearances last season, finishing with a 3.76 ERA.