Marc VDS rider Morbidelli had been cleared by doctors on Thursday to race at the Sachsenring after fracturing his hand in a practice crash at Assen, taking part in first practice on Friday with a plate inserted in his hand.
He was only 22nd fastest, 1.937 seconds off the pace of Andrea Iannone up front.
It was announced shortly afterwards that Bradl will take Morbidelli's place for the remainder of the weekend, marking the German rider's first MotoGP start since Valencia 2016.
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After losing his Aprilia ride, Bradl raced for Honda in World Superbikes in 2017 and then switched to a MotoGP test rider role with the Japanese marque this season, with three wildcard appearances planned.
The first of these will be at Brno next month, with further outings expected at Misano and Motegi.
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