David Moyes saw his injury worries mount up as West Ham were held to a 1-1 FA Cup draw by Bristol City.
Lucas Paqueta set up Jarrod Bowen's goal after just four minutes, but limped off shortly after with a recurrence of a knee injury.
Defender Konstantinos Mavropanos was also forced off with a shoulder problem before half-time.
But most worryingly of all, top scorer Bowen had to be helped from the pitch after the final whistle having gone down injured in stoppage time.
The injuries may have brought into question Moyes' decision to play his strongest team against the Championship side.
But the Hammers boss insisted: "I had no intention of doing anything else than making sure we put out as strong a team as we possibly could.
"Injuries are part of football, and unfortunately we picked up a couple today. Losing Lucas was a big turning point in the match."
The Hammers looked on course for a comfortable afternoon when Bowen brought down Paqueta's ball over the top and fired them into an early lead.
It proved to be anything but, however, after a second-half equaliser from Tommy Conway secured a replay for the rocking Robins.
West Ham's squad would have been given a whole a week off had they won this third-round tie, but they will now be dragged back in on Friday as Moyes, who reached Wembley twice as a player with City, prepares for a return to Ashton Gate.
A replay is the last thing Moyes needs as the injuries begin to bite, but he claimed: "I'm looking forward to going back to Bristol, I've not been there for a long time, I'm really looking forward to going back to Ashton Gate.
"The amount of games we played this season it would be better if we didn't have it, but if I was Bristol City I'd be thrilled to have West Ham at Ashton Gate."
Danny Ings has been linked with a move to Wolves this January having hardly figured this season.
The striker, on as a second-half substitute, missed a late chance when he hit the side-netting.
But Moyes insisted: "Danny was probably the best player when he came on. I'd talk about his performance rather than anything else."
City boss Liam Manning, a former Hammers Under-23s coach, was delighted with his side's second-half display.
"The immediate emotion would be pride in terms of the performance level," he said.
"Going a goal down early can derail you but the response was outstanding.
"For the first 20 or 25 minutes of the second half the performance level was excellent, and the goal was a terrific moment of quality."
*copy from PA.
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