Marco Reus has been rated as a major doubt for Borussia Dortmund's match against Bayern Munich at the end of the month.
Dortmund boss Peter Stoger was quoted by ESPN, admitting that the forward would likely miss the game against the Bundesliga leaders on 31st March due to muscle stiffness.
Reus only returned from a lengthy cruciate knee ligament injury in February, and has been missing for the past couple of weeks after he encountered problems with muscles around the area in the Europa League defeat to Red Bull Salzburg.
The 28-year-old sat out the win over Hannover last weekend because of the ongoing situation and, asked if he'd be available to face Jupp Heynckes' runaway leaders in just over a week's time, Stoger was adamant that that wouldn't be the case.
He said: "I wouldn't bet on it. It was always clear that there'd be difficulties. Within a short period of time, he helped us a lot."
Reus has been plagued by numerous injury issues over the past few seasons as he struggles to get a grip on his fitness and help Dortmund become title contenders once more.
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The 28-year-old has missed a mammoth 59 games over the past two seasons due to knee, thigh, heel and groin problems and the winger has been a huge miss to Die Borussen as they struggle to try and move up Germany's top flight.
Dortmund find themselves sitting in third position only one point behind second-placed Schalke, but they are a massive 18 points off Bayern who have all but wrapped up the league trophy at this early stage of the campaign.
Reus has bagged 92 goals in 198 appearances in all competitions for the Westfalenstadion-based club, and his end product has been sorely missed by Stoger's men as they try to become a dominant force in Germany and on the continent once more.