3. Trey Marshall
There are two other players that you could consider for this third and final spot but Trey Marshall seems to make more sense than the other two. Joshua Kelley and Trey Pipkins could both bet cut candidates but the Chargers need their depth.
Anyone who reads my work on Bolt Beat knows I am not a Kelley fan in the slightest and think he is a terrible running back. That being said, Justin Jackson is extremely inconsistent and as bad as the running back room it, it has to stay four deep for now. Kelley probably should be waived, but he should be waived for another running back, not for Johnson.
Pipkins is horrible and another whiff of a draft pick. That being said, the Chargers need bodies to play tackle, especially with the offensive line already down two starters.
Marshall has not really done much for the Chargers this season as he got his first true taste of playing time on the defense in Week 10 against the Minnesota Vikings and he was not very good. Marshall has instead been kept on special teams and there he has not been very good, either.
Marshall was waived by the Denver Broncos before the season and the Chargers picked him up. His value obviously is not that high and with Nasir Adderley and Michael Davis getting healthy, the team can probably afford to part ways with Marshall.
And even if the Chargers do battle injuries again at safety there are other options that the team can take. I would much rather see rookie Mark Webb get the emergency snaps to develop as a player and see what he has rather than give snaps to a special teams player who probably won't be on the team next year regardless.