I could see them signing Rachaad White to a cheap contract.
The teams only concern is given Charbs health, this draft class is quite weak at RB so its curious we didnt sign anyone today. I do suspect given how they acted today they're likely targeting one of Mike Washington, Emmet Johnson, or Singletary (depending on health), the first two who'd be suitable replacements for Walker's athleticism.
Going through the list of RBs by team, I'm guessing the roll of the dice JS is making is that there's a good chance neither Washington or Johnson will be drafted before the 4th round, probably only have 4-5 teams even looking to invest draft capital that high on the position (MIN, DET, WAS + SEA all have a need and then maybe JAX/TEN/IND/CIN/ATL could go that early too). Given the class being so weak in general, JS probably just banking on the lack of necessity will make most teams who already have 2 quality RBs to not even bother that early on any of them. If he's wrong though, I'm guessing his plan is to just see how things shake out as the offseason + season progresses. He's known to make in-season trades and maybe he figures there's always at least one bad team looking to offload a quality RB if they can get something for him.