Bayern Munich star Robert Lewandowski is an injury risk ahead of Real's match
Lewandowski was seen limping out of training ahead of Bayern’s clash with Borussia Dortmund on Saturday.
The Poland international briefly spoke to manager Carlo Ancelotti before leaving the training field.
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Bayern are already struggling, with fitness concerns over Thomas Muller and Manuel Neuer.
But losing Lewandowski so close to the first leg in the Allianz Arena would prove a major dent to their European ambitions.
German newspaper Bild claim Lewandowski (right) left the training field
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Lewandowski has scored seven Champions League goals for Bayern this season
Bayern beat Arsenal 10-2 on aggregate in the last-16 of the Champions League, while Real qualified for the quarter-finals by edging Napoli 6-2.
The Bundesliga champions host Real on Wednesday, with the second leg scheduled for Tuesday April 18.
Lewandowski has scored seven of Bayern’s 24 Champions League goals this season.