Thornburg (back) is likely headed for the DL to start the season, but the Red Sox won't know until further testing is done Tuesday, Jason Mastrodonato of the Boston Herald reports.

EDGE Analysis

Thornburg was scratched from his appearance Monday due to an upper right trapezius spasm, and the latest setback will likely mean a stint on the DL to begin the season, general manager Dave Dombrowski confirmed. Scott Lauber of ESPN noted the injury is not related to the shoulder weakness that had sidelined Thornburg previously, which is positive news. The 28-year-old will head for an MRI on Tuesday, and there will likely be a firmer timetable after the results are disclosed. With Thornburg likely out for some time to start the season, Joe Kelly will presumably slide into the setup role, while Robby Scott is now a candidate to make the Opening Day roster as the third lefty in the bullpen.