Johnston was limited at Wednesday's practice due to a chest injury.
The Chargers' receiving corps is banged up at the moment, with all of WR Ladd McConkey (foot, DNP on Wednesday), WR Brenen Thompson (quadriceps, LP) and TE Charlie Kolar (forearm, LP) dealing with health concerns, and WR KeAndre Lambert-Smith (hamstring) and TE David Njoku (fibula) on IR. Johnston has had every opportunity to produce this season, with at least a 75 percent snap share in all four games, but he so far has just nine touches for 111 yards from scrimmage and no TDs. Assuming McConkey isn't able to play Sunday versus the Broncos and Johnson suits up, the latter could be the unquestioned No. 1 pass catcher for QB Justin Herbert.