Welbeck landed awkwardly after leaping for a header 25 minutes into Arsenal’s Europa League tie against Sporting.
As the England forward landed his ankle ostensibly gave way under him, leaving the 27-year-old very distressed.
Players quickly gathered around Welbeck and the medical team was rushed on to help.
After being a lengthy period of care on the ground, including oxygen, the Arsenal man was stretchered off to rapturous applause.
The north London club soon posted their well-wishes for Welbeck upon announcing his substitution online.
“After a lengthy delay, it’s going to be a sad end to tonight’s game for Danny Welbeck,” a tweet from Arsenal read.
“Welbz is substituted to the sound of Emirates Stadium chanting his name.
“We’re all hoping for the best for you, Danny.”
Mesut Ozil was rested for the game and posted his best wishes on Twitter, also.
“Oh no … get well soon Danny,” the German international wrote.
The shock in the faces of surrounding players could be seen when Welbeck hit the deck, with BT Sport commentator saying: “Obviously the medical team here will give him as much time as needed.
“And the look on the players’ faces is worrying isn’t it. Look at that.
“I have to tell you there is some concern here and you can see it on those faces.”
“Matteo Guendouzi among those looking on. Horrible to witness, always.
Welbeck has been plagued with injuries during his career, missing over 93 senior games through being on the sidelines.
In fact the former Manchester United striker had never suffered an ankle injury until his unlucky fall on Thursday.