LONDON - Zlatan Ibrahimovic's superb season with Manchester United appears over after the club announced he had sustained a serious knee injury in Thursday's Europa League clash with Anderlecht.

United revealed that both the 35-year-old striker and Argentine defender Marcos Rojo picked up knee injuries in the same match.

"Detailed investigations on the injuries sustained by Marcos Rojo and Zlatan Ibrahimovic during Thursday's Europa League match have confirmed significant knee-ligament damage in both players that requires specialist opinions over the coming days," a statement read on United's website.

"Estimations of time to full recovery will only be possible once definitive treatment plans have been decided after these consultations."

Ibrahimovic didn't play his best game against Anderlecht as Marcus Rashford edged United through to the semifinals after extra time.

However, the Swede's goals this season have been a huge factor in the club's improved form. The former Juventus, Inter Milan and Barcelona forward has defied many doubters since joining United on a free transfer from Paris Saint-Germain last year, scoring 28 goals and inspiring Jose Mourinho's United to victory in the League Cup.

Meanwhile, Rojo's injury is a serious setback to United in defense, with England international central defenders Phil Jones and Chris Smalling expected to be out until mid-May.

Ibrahimovic's one-year contract expires at the end of the season, meaning it is possible he has played his last game for the club.

Recent speculation has linked him with a move to Major League Soccer in the United States.

His absence looks certain to hinder United's Europa League hopes and its chances of securing a top-four finish in the Premier League.

At times he has carried the team this season, and his fantastic form has earned him a PFA Player of the Year nomination.

A United victory over Burnley on Sunday would cut the gap to fourth-place Manchester City to one point and make Thursday's derby at Etihad Stadium even more intriguing.

However, the Europa League appears to offer United a stronger chance of Champions League qualification.

If it can get past Spanish side Celta Vigo over two legs in the semifinals, either French side Lyon or Dutch outfit Ajax will stand between United and a maiden triumph in the competition, and with it a place at Europe's top table next season.

Ander Herrera and Ashley Young, described by Mourinho as "fresh to play" after not featuring in midweek, appear set to start at Turf Moor, where Burnley has won 10 of its 16 league games this season.

Agence France-Presse