Pramac has officially confirmed that Ducati test rider Michele Pirro will replace Danilo Petrucci until his return from a second round of hand surgery.

Petrucci, who had impressed during pre-season testing on the team's Desmosedici GP15, sustained multiple fractures in his right hand during a testing fall at Phillip Island last month, but travelled to Losail to try and compete in the season opener.

Initial results were positive, but Petrucci was left in pain at the end of FP3 and a subsequent X-ray showed a dislocated bone segment of the third metacarpal, meaning some fractures that had been sealed by surgery had re-opened under the stress of riding.

Petrucci underwent a second operation on Monday and will definitely sit out the upcoming Argentina round. Indeed, sources close to the team fear he will not be fit until round five at Le Mans.

Following speculation that Ducati test rider and retired double world champion Casey Stoner might step in, something the Australian ruled out during private testing in Qatar on Monday, Pramac has now declared that Pirro 'will run until the return of Petrux'.

Pirro entered three MotoGPs last year with the GP15 - as used by Pramac this season - taking points finishes at Mugello and Valencia. He also qualified an excellent fifth at Misano, but suffered technical problems on the grid.