WASHINGTON (AP) The Nationals say pitcher Stephen Strasburg has been diagnosed with a strained left trapezius, an upper back muscle where the arm meets the neck.
Strasburg left Friday's start at Cincinnati after 16 pitches and was put on the disabled list the following day. He was examined Monday was team doctors in Washington.
Washington manager Matt Williams said Tuesday the trapezius was the cause of the neck and upper back discomfort. Strasburg is 3-5 with a 6.55 ERA in 10 starts and failed to last four innings in four of five outings in May.