It looks like Don Jones’ injury was serious, as he posted on his personal Snapchat that he tore his ACL (h/t: Manvir Mundra on Twitter). Jones left Thursday’s final preseason game against the Los Angeles Chargers with an injury, and it looks like he’ll soon be waived/injured by the 49ers before going on injured reserve for the year.

Jones, a defensive back, was left off of most 53-man roster projections, though he was a well-liked special teams player. He joined the 49ers this offseason and was trying to earn a spot on the safety depth chart.

He’s played in 56 games, but went into this offseason with just three career snaps on the defensive side of the ball. That’s because the bulk of his snaps has been on special teams, where he’s been an effective tackler and consistent performer.

It’s unlikely he would have made the final roster, but it’s still disappointing to see such a serious injury to a bubble player trying to make an NFL roster. I would think this increases the chance that Adrian Colbert makes the final roster as a special teams gunner.