Thames (back) didn't participate in Sunday's simulated game, Mark Zuckerman of MASNSports.com reports.

EDGE Analysis

Thames' stiff back prevented him from taking competitive at-bats for the second day in a row, prompting manager Dave Martinez to label the first baseman as "day-to-day" heading into Tuesday's series opener versus the Mets. Fortunately for Washington, Howie Kendrick looks to have overcome his own back issue since the Nationals had their weekend series in Miami postponed. Kendrick or Asdrubal Cabrera could pick up starts at first base if Thames isn't ready to go when the Nats return to action.