Johnston tallied two catches on three targets for nine yards in Sunday's 36-34 loss to the Dolphins.
Despite the fact Mike Williams was sidelined for part of the first half due to a head injury, Johnston only saw 22 offensive snaps, far below supposed No. 4 wide receiver Joshua Palmer's 55. It's possible the Chargers simply want to ease Johnston into NFL action, but the big-bodied first-round pick was expected to fill a significant role right away. His fantasy upside in Week 2 against the Titans could depend on Williams' availability.