Will Still has confirmed defender Welington suffered a badly twisted ankle in Southampton's 2-1 home defeat against Stoke City.
Left wing-back Welington picked up the injury in the first half and after lengthy treatment was taken down the tunnel on a stretcher and replaced by Ryan Manning.
"Yes, it's not great," Southampton manager Will Still said when asked for a post-match update on the player.
"He's twisted it badly, it's his ankle and he's already had issues with that so it doesn't look hyper positive."
Welington's injury was an additional setback for Still on top of the result, his first defeat as Southampton manager.