Nationals manager Dave Martinez said Sunday that Strasburg (shoulder) doesn't have a clear timetable to return from the 10-day injured list, Dan Kolko of MASN Sports reports.
Martinez noted that the decision to place Strasburg on the IL was made after he felt off during his usual between-starts bullpen session, prompting the Nationals to send him in for an MRI. With the MRI revealing inflammation in his right shoulder, Strasburg will likely back off throwing for at least a few days before the Nationals check back in and see how he's healed. Until Strasburg begins throwing again off a mound, a firm target date for his return is unlikely to emerge. Paolo Espino was summoned from the Nationals' alternate site to replace Strasburg for a spot start Sunday against the Diamondbacks.