The Austrian international has been revitalised in recent weeks as he has been given licence to attack in the midfield role supporting Jason Scotland up front.
However as a result of three games in a week (Scharner was on international duty last week), the flamboyant midfielder has suffered his hip injury.
Now a big doubt for Saturday's clash with Burnley, Scharner is rated at no more than 50/50 to take part.
Chris Kirkland is also a doubt for the game with what appeared to be a dislocated finger, also suffered in the Manchester City game.
Speaking on the injuries, Martinez told the club's official website: "We have two doubts in Paul Scharner and Chris Kirkland. Scharner has a hip problem and he'll be assessed in the next two sessions before the game, and Chris is also 50-50 and will too be assessed over the next 48 hours."
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