West Ham joint chairman David Gold fears Manuel Lanzini could be out for up to six weeks after limping out of Saturday's 2-0 win over Liverpool with a groin injury.
The Argentinian departed the action towards the end of the first half of the Premier League clash at Upton Park and was replaced by Pedro Obiang.
Manager Slaven Bilic confirmed after the game the Lanzini had sustained a groin problem, and expressed his hope the attacker would "only be out for a short time".
However, Gold later took to Twitter to discuss the injury, and voiced his concerns over the severity of the problem.
"We will know more about Manuel's injury after the scan on Monday but it could be 4/6 weeks. He was superb today," Gold posted.