Understanding perhaps, the reigning six time MotoGP world champion made a later start than most - only the sick Casey Stoner completed less laps - but the Italian found time to test electronics, tyres and a 'long life' version of the YZR-M1 engine during his 58 laps.
The 'long life' engine will be needed from Brno (round eleven of 17) onwards, when new rules will limit each rider to five engines until the end of the season. The penalty for any additional changes will be 10 points and - with Rossi, Lorenzo and Stoner now tied at the top on 106 points - such a penalty could prove disastrous.
Rossi finished the test second fastest, 0.204 seconds behind Repsol Honda's Andrea Dovizioso and just 0.012s ahead of Lorenzo.
"It was hard to test after yesterday but it was a good day and we found out some important things," said Rossi. "We worked on electronics to try to find a better power delivery and we also checked a different version of the engine for the second half of the season. Finally we also tried a new tyre with Bridgestone.
"We got good feedback and hopefully today should mean I can feel even better on my M1 than I did at the weekend, which was already pretty good. At the end we also tried to set some fast qualifying' laps and I made a good time, so we're happy. Now I am going home to Italy to have some rest."
"Of course it wasn't easy to go back to work after such an intense day yesterday and to ask Valentino to get back on the bike, but we tested all afternoon and it was well worth the effort, added team manager Davide Brivio. We did some good work and collected important information that will help us through the next busy stage of the championship."
Rossi will fight for his 100th grand prix victory next time out at the Dutch TT, held at Assen.