Michele Pirro was fastest in Friday's first practice session for the San Marino and Rimini Riviera MotoGP, clocking a time of one minute, 31.909 seconds.
Veteran rider Pirro is competing at Misano Adriatico as a wild card for Ducati satellite team Aruba.it Racing and finished 0.115 seconds ahead of fellow Italian Luca Marini.
Jorge Martin, who sits second in the overall standings and trails leader Francesco Bagnaia by 50 points, was 0.157sec back in third.
Reigning world champion Bagnaia finished down in 20th, 0.690sec behind Pirro in a tentative session hampered by injuries from his horror crash at the Cataluyna GP last weekend.
The reigning world champion flew off his bike at Montmelo before being run over by Brad Binder but has been cleared to race at his home track on Sunday.
However Bagnaia is still recovering from his accident and could do little more than try to stay on his Ducati ahead of Friday's second practice session at 1300GMT.