Andrea Dovizioso dropped down the leaderboard in FP2 at Valencia in Spain to find himself languishing in 14th place, although the Ducati rider placed seventh in the day one standings based on his time from FP1.
Dovizioso ended the morning session fourth fastest after a lap in 1m 31.642s but was unable to better his time in the afternoon, when the Italian struggled for rear grip with the soft tyre.
“It was a very difficult afternoon in that there was not much grip on the track and it was very difficult to control the bike,” said Dovizioso.
“I was not able to do even one clean lap, because I made several mistakes which were caused by lack of grip. The rear tyre also showed an odd pressure drop so we now have to try and understand the reason why.
“In any case we must improve my feeling with the bike for tomorrow and so we'll be working in that direction.”
Ducati Test Team rider Michele Pirro was 13th overall as he prepares for his third race of the season as a wild card entrant at the Spanish circuit.
Pirro, who lapped in 1m 32.399s to set his best time in FP2, said he was yet to find a good feeling with the Desmosedici GP15 at the Ricardo Tormo circuit.
“It wasn't an easy day, because I still haven't found a good feeling with the bike and I wasn't able to be as fast as I would have liked,” he said.
“We worked on both bikes, testing some new detail parts and now we have to analyse the results to see what we need tomorrow in order to improve our times.
“My goal is to get inside the top ten and directly into Q2: my bike is going strong and so it's only a question of feeling, but tomorrow I'm sure we'll manage to find it.”