Slaven Bilic says West Ham have been dealt a "big blow" after striker Andy Carroll was ruled out of Sunday's Sky Super Sunday clash against Swansea City with a groin strain.
Carroll made his first appearance of the season in September after spending eight months out with a tear in his medial ligament.
He scored his first goal in nine months after coming on as a substitute in West Ham's 2-1 win over Chelsea on October 24, but has not scored since.
"We have the Andy Carroll situation where he is feeling his groin and he could miss the Swansea game which is a big blow. It's one game," the Hammers boss told his pre-match news conference.
"It's nothing major. The scan showed a little bit of a problem. Not long term but it's very unlikely he's going to play."
West Ham are eighth in the table and despite a run of six games without a win, Bilic is confident his side can pick up three points by exploiting spaces in Swansea's defence.
"The key to beating Swansea? I watched their last five games and they didn't play the best. Sometimes they showed good quality going forward but they were open at the back," Bilic said.
"We must be as compact as them and then we have the quality to beat them. We have to show more quality in the final third.
"I'm really confident for Sunday's game against Swansea and if we keep the team spirit when players come back, it's all positive."
Watch Swansea v West Ham live on Sky Sports 1, Sunday from 3.30pm.