The Black Cats entertain Wigan Athletic this weekend with only five points separating them from Blackpool in the first of the relegation places.
Steve Bruce's side have lost eight of their last nine matches in the midst of a mounting injury crisis, and things are unlikely to get much better before Roberto Martinez's side travel to Wearside on the back of a crucial 3-1 win at Bloomfield Road.
Welbeck only returned from a two-month injury lay-off at the start of last month, but as has been the case with a number of Sunderland players this season, the Manchester United loanee has quickly picked up another problem.
He complained of tightness in his hamstring during the second half of Saturday's defeat, and was eventually withdrawn in the 71st minute.
He is regarded as a major doubt for this weekend's game, and with Fraizer Campbell already ruled out of the remainder of the campaign, Asamoah Gyan is likely to be the only experienced striker available to Bruce.
Danny is a doubt for this weekend, he has to be, said the Sunderland boss. We don't think it's as bad as last time, but he is very doubtful for the next game. We don't know quite how serious it is yet, but knowing our luck, I'd be amazed if it didn't put him in doubt.
I've never had a run like this in terms of injuries before and, especially up front, we haven't really had enough to cope. (Darren) Bent wanting to leave, Campbell re-injuring himself, it's all affected us.
Hindsight is a wonderful thing, but we took a calculated gamble in January and, looking back now, it's made things very difficult.
Kieran Richardson, who failed a late fitness test ahead of the Birmingham game, is likely to be available to face Wigan, and the England international is expected to play in an attacking midfield position on the shoulder of Gyan.
The situation is hardly ideal given the magnitude of Saturday's match, with Sunderland having tumbled to 15th position at the weekend.
Defeats for Blackpool and West Ham prevented a bad situation becoming worse, but after being ensconced in a top-six position as recently as February 5, the Black Cats now find themselves in a full-blown relegation fight.
It's incredible what has happened really, but you can't take anything for granted in this league and we've certainly been up against it for the last couple of months, said Bruce. The only thing you can do in our position is accept the challenge.
We've got five games left, and three of them are at home. Can we go and get a couple of results and end the season with a flourish
The two back-to-back home games (against Wigan and Fulham) are obviously huge for us now. I think one win will do 41 points will keep us up.
After the previous weekend's desultory display against West Brom, at least Bruce was able to take some positives from Sunderland's improved performance at St Andrew's, even if the result was every bit as depressing.
Jordan Henderson produced an eye-catching display on the right of midfield, while Killingworth-born Jack Colback impressed as he made his first Premier League start.
If we play with the same refreshing attitude we played with here, surely we will be okay, said Bruce. We've played really well, and although we haven't taken anything from the game, we have to take the positives from that.
We're in there, there's no doubt about that. But I still think there are ten teams in it with five games to go, and we have to include ourselves in that. I think the players are intelligent enough to know that we haven't got enough points yet.