Scans have confirmed that Middlesbrough striker Afonso Alves suffered a broken foot against Newcastle United on Monday night.
The Brazilian striker was stretchered off in the first half of the 3-1 defeat following a challenge from Magpies midfielder Nicky Butt.
Boro boss Gareth Southgate spoke of his fears that Alves would miss the club's last two games of the season, and now the blow has been confirmed.
The former Heerenveen attacker, who has netted seven goals this season, will be absent for the matches at home to Aston Villa and away to West Ham United.
A statement on the club's official website said: "Afonso Alves' season is over after Gareth Southgate this afternoon confirmed the striker fractured a metatarsal in his foot during last night's defeat at Newcastle.
"He will take no further part in this season's campaign after scans this morning revealed the extent of the injury.
"Meanwhile, club captain Emanuel Pogatetz has had a successful knee operation but will also miss the rest of the season and is expected to return towards the middle of pre-season training.
"Didier Digard missed the game because of a groin injury picked up in training and is a doubt for Saturday.
"And David Wheater is also struggling to be fit in time for Aston Villa because of a knee injury that ruled him out of last night's game."
The Teesside club currently find themselves in the relegation zone, three points adrift of safety.