2. Joshua Kelley
Carrying four running backs is definitely an interesting decision as three is all the team really needs. You could make the case for two running backs to get waived before Johnson and I would have preferred Joshua Kelley over Justin Jackson.
I get that Jackson cannot stay healthy but someone would have likely claimed him. While there is a chance that Kelley would have gotten claimed, it is not as much of a guarantee.
Kelley was statistically the worst running back in the league, in terms of DVOA, last season. He would not have been this must-sign running back if waived. He would have been a late-round running back who was bad last season.
And even if Kelley was claimed the Chargers could have easily replaced him or gotten a better option if it came to that. Remember last season when the team signed Troymaine Pope AND Kallen Ballage, both of which were better than Kelley?
Having four running backs, especially with a fullback, is a waste of roster space, in my opinion. It is not like Kelley is even good in special teams either, so other than Tom Telesco not wanting to give up on a 2020 draft pick this early (but he did with Joe Reed) I cannot see why else he is on this roster over Johnson.