Leading marksman Kenwyne Jones missed out on the weekend's victory over Aston Villa with a flu virus, while Carlos Edwards (groin), Danny Collins (dead leg) and Nyron Nosworthy (ankle) have been laid low by injuries.
Both Jones and Edwards will miss out on Trinidad and Tobago's midweek friendly international against Jamaica.
Sunderland boss Roy Keane, whose delight at Saturday's first away win of the season was tempered by the injury setbacks, said: "We'd lost Kenwyne Jones to a virus which was always going to make it difficult for us at Villa.
"He's a very important player for us, but, ironically, it probably made us play better football because, obviously, when you've got a player like Kenwyne in your side, the tendency is to go long because he's so good at getting on the end of things.
"But he missed training the day before the game with the virus and there's no way he could have been involved in the game against Villa.
"Carlos has a slight groin problem. He picked it up in training the day before, so we didn't want him playing the full game.
"Neither of them will be fit enough to travel on international duty this week.
"Nyron picked up a knock in the game, as did Danny, so we'll just have to wait and see how they come along.
"There were plenty of ice packs in the dressing room, but then there usually are – there'd be something wrong if there wasn't after a Premier League game."
Jones is likely to be the biggest doubt for the game against West Ham, who have bounced back from three successive 4-0 drubbings to beat Blackburn and hold Everton to a draw at Goodison Park.
Despite the fact that Sunderland played well without him at Villa Park, the five-goal top scorer would be expected to make an immediate return once fit.
The Edwards groin strain should clear up in the next few days with rest and Collins and Nosworthy will both be desperate to face the Hammers at the Stadium of Light on Saturday.
Nosworthy took a bad knock towards the end of the first half at Villa and it looked as though he would not be able to continue, but he soldiered on and was able to get through the game. Collins also got through the full 90 minutes with the knock.