London (AFP) – West Ham announced Wednesday that their club-record signing Andre Ayew is facing “a significant rehabilitation period” as a result of the thigh injury sustained in Monday’s Premier League match at Chelsea.

Ayew, who joined the Hammers from Premier League rivals Swansea for £20.5million (24 million euros, $26.7 million), lasted just 35 minutes of his West Ham debut at Stamford Bridge before limping off.

West Ham have not specified for how long Ayew will be sidelined but Jack Sullivan, the son of the London club’s joint-chairman David Sullivan, earlier wrote on Twitter: “We are devastated that Ayew will be out for about 4 months. He needs surgery.”

The club’s head of medical and sports science Stijn Vandenbroucke issued an update on West Ham’s official website.

“Andre Ayew injured his right thigh at Chelsea on Monday and underwent a scan on Wednesday afternoon,” he said.

“The medical team will now assess the results with a leading consultant before drawing any conclusions.

“My first thought and priority is with the player and his physical and mental well-being. 

“He has suffered a significant injury and it is imperative that we do not rush to conclusions and we receive the correct diagnosis by consulting top specialists.

“At this time, it is too early to put a time frame on his potential return date but Andre is facing a significant rehabilitation period.

“The best thing we can do as a club is to support Andre through this difficult period. We will keep you updated throughout this process and I am sure he will come back stronger than ever.

“Everyone at West Ham United wishes Andre a speedy recovery and return to action.”

Ayew’s absence is a major blow for manager Slaven Bilic, who had spent the pre-season trying to bolster his attack before finally signing the Ghana star last week.