The Arsenal forward was stretchered off in the first 30 minutes of the 0-0 draw in Portugal after landing awkwardly on his ankle following an aerial challenge with full-back Bruno Gaspar.
"Danny remains in hospital and will continue to be assessed".
"This injury is very big for him, for us and for everyone".
"It wasn't easy to play a good game here, it was all the conditions to play badly, but I think we could have done better". We are going to wait [for updates].
"I didn't see it because obviously I'm at the other end of the pitch so I didn't see exactly what he'd done", said Holding.
Arsenal haven't been behind for a single minute in eight Premier League matches against Wolves - only one team has ever played more games against an opponent without falling behind (Chelsea v Portsmouth, 14 games). I hope we will finish in the first four.
But a 15th game unbeaten for Unai Emery's side at least assured them of European football after the turn of the year with two group matches left to seal top spot.
Doctors are waiting for the swelling to reduce before making a definitive diagnosis - but there are concerns Welbeck has suffered a break, dislocation and ligament damage. Welbeck was available for sale in the summer, Arsenal had not offered him a new contract and likely are not planning to do so.
"It would just take all the uncertainly away and that would help his rehab on the mental side of it". I think that link through the club is stronger than ever.
Welbeck may have suffered a "career ending" injury, according to medical expert Johnny Wilson.