The England international suffered a horrific broken ankle on Thursday night during the north Londoners’ 0-0 draw with Sporting Lisbon.
Welbeck, 27, was immediately transferred to hospital to receive treatment on his right leg, which got trapped in the turf.
The former Manchester United man’s latest injury setback is expected to keep him on the sidelines for the next four months.
Hours after the match, Emery took to Twitter to send his well wishes to the striker, whose future at the Emirates is well and truly up in the air.
“One more big reason to fight and win next Sunday,” the Arsenal boss tweeted.
“All the @Arsenal with you. Hope to see your smile and energy soon, Danny!”
Like his Arsenal players, Emery is fearing the worst for fan-favourite Welbeck.
“This is the worst news tonight,” Emery said. “We think it’s serious. He was working well, doing a good match. He had chances.
“His injury also affected the mentality of the players. They saw it was a big injury.
“When you are playing football, playing competitive matches, it can happen. We don’t want that but this is our profession.”
Several of Welbeck’s current and former team-mates took to Twitter to wish him a speedy recovery.
Former Arsenal midfielder Santi Cazorla, who himself was plagued by injuries, tweeted: “Get well soon my friend.
“These are the worst things in football but I know you are strong and you will come back, you deserve the best my man.”
Gunners centre-back Rob Holding believes Welbeck can ‘come back strong’ from his horror injury and has claimed the team will do everything in their power to keep his spirits high.
“He’s been so unlucky with injuries over the past few years but he’s a good character and got a good set of lads around him,” he told the London Evening Standard.
“So we’ll lift him up and get him back as soon as we can. He can come back strong.”