Czech Republic captain Tomas Rosicky looked set to miss the rest of Euro 2016 after picking up a thigh injury in their 2-2 draw against Croatia in Saint-Etienne on Friday.
"He definitely won't be playing in any match in the coming days and certainly not against Turkey.
"The treatment time is very individual but it ranges between three to six weeks," he added.
"It doesn't look good."
The midfielder was a risky inclusion in Pavel Vrba's squad having not played a single league game at Arsenal last season, and underwent a scan on Saturday after being injured late on against Croatia.
The CzechRepublic fought back from 2-0 down to take a point having lost their opener against Spain, and face Turkey on Tuesday in their final Group D match.
Image: Czech Republic's Tomas Rosicky
Photograph: Jason Cairnduff Livepic/Reuters
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