The Arsenal striker is set to miss nine months with an injury picked up against Manchester City.
The striker, who only returned from a long-term injury earlier in the year, pulled up with a knock in the 2-2 draw with Manchester City last weekend.
It appeared to be another bad injury for the forward and that was confirmed this week, with scans showing he had suffered cartilage damage in his right knee.
He will undergo surgery this week and then faces a gruelling nine months of recovery that will see him miss Euro 2016 and some of next season.
It is horrendous luck for the striker, and Wenger says everyone at the club is devastated for him.
“We’re all devastated, and Danny even more so,” Wenger told Arsenal Player.
“We can only feel sad and support Danny now in order to get him back. Danny has to deal with it unfortunately. We just have to give him the maximum support we can and show him that we trust he can come back.”
The injury to Welbeck will now surely see the Gunners move for a new striker in the summer transfer window.
The position has long been a problem one at Arsenal, but Wenger has refused to buy in it as he has stuck with the likes of Welbeck, Olivier Giroud and Theo Walcott.
The latter two have not worked out, and with Welbeck’s injury leaving them short for next season, a new striker must surely be top of their wish list.