The wiki doesn't show any back injury for Saquon Barkley in 2026. He's been dealing with a hamstring strain that cost him Weeks 5-6, but he returned Week 7 and lit it up — 49 yards and a TD on his first three carries against the Cowboys (from the Saquon Barkley page).
If you saw something about a back issue, it may be outdated info from a prior season or a different player. As of the latest wiki update (Week 7+), Barkley is healthy and playing through a massive workload with both Tank Bigsby and Will Shipley on IR.