West Ham striker Andy Carroll has been ruled out for between four and six weeks with a knee injury.
The 27-year-old was injured during Thursday’s 1-1 draw away to Romanian champions Astra Giurgiu in their Europa League play-off first leg.
Hammers boss Slaven Bilic told BBC Sport: “Hopefully it will be four weeks. It’s nothing major. But it’s very sad for him and us.
“It’s a big problem for us without him. We’re counting on him big time.”
Earlier this week, Bilic lost £20m club-record signing Andre Ayew to a thigh injury for four months.
Carroll has had a series of injury setbacks since joining West Ham from Liverpool in 2012, initially on a season’s loan before the deal was made permanent.
The forward, who has played nine times for England, has spent about half of his time at the club out injured.
His latest setback adds to a growing casualty list for Bilic.
Aaron Cresswell, Sofiane Feghouli and Manuel Lanzini are also out injured, while midfielder Dimitri Payet is still regaining full fitness, having been given a break after helping France reach the final at Euro 2016 in July.
Subscribe to the BBC Sport newsletter to get our pick of news, features and video sent to your inbox.