Running backs: Austin Ekeler, Justin Jackson, Joshua Kelley, Larry Rountree III (4)
No real surprises here. Austin Ekeler is clearly RB1 and Justin Jackson is RB2 from a talent/experience perspective. The Chargers invested recent draft capital into both Joshua Kelley and Larry Rountree III that make them difficult to cut.
Jackson's health still could go a long way in determining the final roster though. He's been nursing a groin injury since the Rams game. There's no real chance that's he's outright cut, but he could start the year on the short-term 3 week IR if it continues to linger. That could open up a temporary spot for Darius Bradwell, or perhaps somebody on the defensive side of the ball.
There are fans who are fed up with Jackson's injuries. The lower body injuries have certainly lingered as of late. In the last two seasons, the former Northwestern back played 16 out of a possible 32 games.
Jackson having a relatively safe roster spot is in my opinion more about what we didn't see in Kelley's development last year. He looked ready to take the RB2 job in those first two games and then transitioned into being a healthy scratch towards the end of the season.
Keeping Kelley and Rountree seems redundant to me and I'd prefer to keep the usual three running backs. While Kelley hasn't shined this preseason, there's little to no chance that Telesco moves off of a fourth-round pick after just one year. Four running backs could be necessary from the standpoint not only from the standpoint of Jackson's health but also the fact that he's entering the last year of his rookie deal.