Vinales fastest during a delayed opening practice for the 2020 Aragon MotoGP.
The session was postponed by 30-minutes due to the cold morning temperatures, but conditions were still borderline.
Zarco fell soon after the action began, with Vinales then saving a front-end lock-up at the same Turn 14 before Marquez fell at Turn 2.
The closing ten minutes saw spills for Lecuona (turn 2) and early leader Morbidelli (Turn 14) before title leader Quartararo suffered a very fast lowside as he braked for Turn 8, another right-hander, at the very end of the session. The Frenchman walked away with a slight limp.
The Ducatis, in particular, played it safe after struggling to generate heat in the tyres.
Valentino Rossi has been forced to miss this weekend’s event after a positive Covid test on Thursday. The Italian is also expected to miss next weekend’s second Aragon round.
HRC test rider Bradl is again replacing injured reigning world champion Marc Marquez.
Official Aragon MotoGP records:
Marc Marquez SPA Honda1m 46.635s (2015)
Fastest race lap:
Jorge Lorenzo SPA Yamaha1m 48.120s (201)