Ducati's MotoGP test rider Michele Pirro will again stand in for the injured Ben Spies at the forthcoming race at Barcelona.
The Italian filled in for Spies in the French Grand Prix, with the American struggling to overcome physical problems precipitated by a heavy crash at Sepang last year.
Spies also missed the preceding race in Jerez, although Ducati did not field a replacement as Pirro was racing its development bike in the first of the three wild card starts he will make in 2013.
After missing two races, Spies did at least start in Mugello, but he was forced to pull out after Friday practice as his persistent shoulder problems proved too severe.
Pirro, making another wildcard appearance for Ducati, finished seventh behind works riders Andrea Dovizioso and Nicky Hayden.