The Boston Red Sox scratched Tyler Thornburg from a scheduled appearance Monday against the Baltimore Orioles because of a spasm in his upper right trapezius.
Thornburg hasn't pitched in a Major League spring training game since March 1 because of weakness in his right shoulder. He "most likely" will open the season on the disabled list.
He is expected to undergo testing, including a possible MRI exam.
"If it's what I anticipate, probably not," Dave Dombrowski said. "But I can't rule anything out because I don't really know anything (other) than what we just found out, that he's got a trap that's tight. If it's a short-term situation, then I don't have a spot to offer somebody."