Commanders head coach Dan Quinn said that Sinnott is dealing with an oblique injury and is unlikely to play in Friday's preseason finale versus the Ravens, Nicki Jhabvala of The Athletic reports.
Sinnott won't practice this week after sustaining the injury this past Saturday. Quinn didn't indicate that the tight end's availability for the Commanders' Sept. 13 season opener versus the Eagles is in any peril, but Sinnott will likely need to return to full practice at some point over the next two-plus weeks to put himself on a path to play.