LCR Honda's Johann Zarco is only the third rider on track in Session 2.
Despite the early afternoon heat, rookie Aldeguer has set a 1m 45.958s to be the only rider other than Marc Marquez to go into the '45s so far today.
Session 2 is officially underway, but most riders and teams are having lunch, with only Fermin Aldeguer and Pedro Acosta having set a lap time.
Practice starts...

Manuel Gonzalez is also taking part in the practice starts during his debut MotoGP test.
Session 1 ends with Marc Marquez fastest from Maverick Vinales, Franco Morbidelli and Fabio Quartararo.
There will now be the first of today's practice start periods, before Session 2 begins at 1:20pm.
Sounds like Pramac Yamaha's Miguel Oliveira was another to suffer a fall earlier today, meaning Monster Yamaha's Fabio Quartararo is up to third place.
Yamaha is thought to have engine, aero and swingarm options available to try.
After Francesco Bagnaia's much-needed front-end progress with the bigger brake disc in Sunday's race, VR46's GP25 rider Fabio di Giannantonio looks to be trying it today.
20mins of Session 1 to go and Marc Marquez is the only rider in the 1m 45s, with VR46's Franco Morbidelli 0.347s behind.
It looks like HRC's Joan Mir, who took his best MotoGP finish since India 2023 with 7th on Sunday, is trying the carbon fibre swingarm that has been developed by test riders Aleix Espargaro and Takaaki Nakagami.
Some pictures from pit lane...

Alex Marquez's 2nd place trophy sits on one of his Gresini Ducatis.

Rear wing and exhaust on Lorenzo Savadori's Aprilia.

Francesco Bagnaia returns on the new Ducati aero.

Manuel Gonzalez is making his MotoGP debut today, with Trackhouse.

Gonzalez leaves the pits.

The new Ducati aero on Marc Marquez's bike.

KTM also has a new fairing, pictured at Tech3.
Reports from pit lane also suggest helmet radios are undergoing further testing today.
Manuel Gonzalez fell from his Trackhouse Aprilia, with Pedro Acosta also reported to have fallen from his KTM. Both riders are OK.
Approaching the end of the first hour and Moto2 title leader Manuel Gonzalez is 2.634s from the top after his first 17 laps on a MotoGP bike.
LCR Honda rookie Somkiat Chantra (6 laps) and Fermin Aldeguer (2 laps) are behind him.
Pedro Acosta, who was thwarted in his efforts to pass Francesco Bagnaia for third in the grand prix, is now between the Ducati Lenovo riders on the timesheets.
It's now a Ducati Lenovo one-two with Bagnaia just 0.029s behind team-mate Marquez.
Manuel Gonzalez improves to a 1m 49.665s, 2.894s behind Marc Marquez.
Trackhouse regular Raul Fernandez has set a 1m 48.170s so far.
Gresini's Alex Marquez, runner-up to Marc in both the Sprint and Grand Prix, jumps straight into the top four on his opening run of the day.
Brad Binder and Francesco Bagnaia climb to third and fourth, but 0.6s from Marc Marquez.
Marco Bezzecchi improves to 0.225s behind Marc Marquez on his 12th lap.
19 riders have now been on track, with only Franco Morbidelli, Fermin Aldeguer and Alex Marquez yet to take to the track.
10:30am: Marc Marquez, Maverick Vinales, Jack Miller, Joan Mir, Johann Zarco, Francesco Bagnaia, Marco Bezzecchi, Fabio di Giannantonio, Raul Fernandez, Brad Binder.