Andrea Dovizioso ended the first day of practice on top of the timesheets, the factory Ducati rider posting a fast lap at the end of the day, as almost everyone stuck in a new tire in pursuit of a fast time.
It was Dovizioso's teammate who garnered much of the attention, however, Jorge Lorenzo suffering a massive highside and causing the session to be red flagged. The cause is still being investigated, but from the onboard video, it sounded like the engine cut out as he tipped the bike in for Turn 3, causing the rear to lock up and come round on him, before spitting him off. Lorenzo fell heavily on his right leg again, on the foot he damaged in the Turn 1 incident in Aragon. Lorenzo was taken to the medical center for further evaluation, but was declared fit to continue, if he chooses to.
Once the track had been cleared of debris and fluids from Lorenzo's bike, the session got back underway again, with riders going after a quick time with a new soft rear. Dovizioso ended the day as fastest, ahead of Maverick Viñales on the Movistar Yamaha. Viñales' fast time should give hope to the Yamaha rider, as he set his quickest lap on a hard tire during a long run. Teammate Valentino Rossi, who finished ninth, also trialed a new aero fairing, with a double winglet at the front of the bike.
Cal Crutchlow took third, again on a soft tire, while Marc Marquez finished in fourth, a fraction behind the LCR Honda rider. Marquez was also using a soft tire, but the Repsol Honda rider was using it on a race simulation, putting 23 laps onto the tire, and lapping consistently in the 1'31s. Danilo Petrucci took fifth place on the Pramac Ducati, just ahead of Andrea Iannone on the Ecstar Suzuki. Iannone had chosen a medium tire, and posted very consistent times on that rubber as well. Alvaro Bautista took seventh spot, ahead of Dani Pedrosa, Valentino Rossi, and Johann Zarco.
The gaps between the whole field were close. The top four were covered by less than a tenth of a second, and the top six were all within 0.166. Four tenths covered the top 11, and the first 17 riders were all within a second.