Pramac Ducati's MotoGP rookie Andrea Iannone plans to switch to the development 'lab' version of the Desmosedici GP13 from the forthcoming German round.
The Italian made the decision after taking part in a private Ducati test at Misano this week, when he completed around 40 laps on the 'lab' bike over two days.
Iannone best lap was a 1m 35.1s, which compares with Jorge Lorenzo's race record of 1m 33.9s.
Ducati development rider Michele Pirro has been race testing the 'lab' bike in recent events, riding alongside Iannone in place of the injured Ben Spies.
However factory Ducati riders Nicky Hayden and Andrea Dovizioso found no real gains when they rode the 'lab' machine at the post-race Catalunya test. It remains to be seen how they feel after this week's Misano outing.
Pirro will continue with Pramac for the German MotoGP event, then be replaced by Moto2 rider Alex de Angelis at Laguna Seca. de Angelis set a best lap time of 1m 37.0s during 50 laps at Misano - his first on a MotoGP bike since 2010.
Spies, continuing rehabilitation on his injured shoulder, hopes to return after the summer break at Indianapolis.