Brentford midfielder Alan Judge fractured his lower leg in Saturday's 3-1 win at Ipswich, the Championship club have announced.
Judge, who started for the Republic of Ireland in their 1-0 win against Switzerland last month, was carried off after two minutes following a strong tackle by Luke Hyam, who was only booked for the challenge but later saw red for retaliating to a Ryan Woods foul.
The Bees have now confirmed that Judge, 27, faces a lengthy spell on the sidelines and looks likely to miss this summer's European Championship.
A statement read: "During today's Sky Bet Championship game against Ipswich Town, Alan Judge sustained a fracture injury to his lower leg.
"The injury was assessed and immobilised locally and Alan has now been transferred to a London hospital where he will be managed by the leading lower limb consultant in the country.
"The nature of his management and long-term prognosis cannot be speculated on at this time, however it should be stated that a full recovery is not in question.
"Alan and his family will receive our fullest support and further comment will be provided as we're able to over the coming days."