The Redskins did not reveal the severity of the issue for Doctson, although they said his status will be updated Thursday.
Doctson was injured after landing hard on the turf while attempting to catch a pass during Wednesday's practice. The 25-year-old left the field holding his arm, per multiple reporters on the scene.
Selected with the 22nd overall pick of the 2016 NFL Draft, Doctson promised a "huge" season in 2018 after missing all but two games during his rookie campaign due to an Achilles injury. Doctson had 35 catches for 502 yards and six touchdowns in 16 games in 2017.
The 6-foot-2, 202-pound Doctson does not have a 100-yard receiving game, nor has he caught more than four passes in a single contest.