The Nationals placed Strasburg on the 10-day injured list Sunday with right shoulder inflammation, Jesse Dougherty of The Washington Post reports.
The transaction is retroactive to Thursday, so Strasburg should be eligible to return from the IL by March 25. Strasburg wasn't known to have been dealing with an injury coming out of his most recent start Tuesday in St. Louis, but the shoulder issue may explain why the right-hander was lit up for eight runs (seven earned) over four innings in the loss. Washington will turn to Paolo Espino to make a spot start for Strasburg in Sunday's game against the Diamondbacks, but Erick Fedde is most likely to stick in the rotation as a fifth starter if Strasburg ends up missing extended time.