Ducati motorsport boss Paolo Ciabatti believes it is "just a coincidence" that Danilo Petrucci's form tailed off dramatically once he was handed a contract extension for the 2020 MotoGP season.
Petrucci joined the works Ducati outfit on an initial one-year deal in 2019 and he was confirmed for a further season in July after a run of three consecutive podiums that included a maiden win at Mugello.
But Petrucci then failed to make the podium again in 2019, and after scoring 108 points in the first eight races before the renewal, he then added only 68 in the 11 races following Ducati's announcement.
"I think that the fact that Danilo's performance was not the same after he signed the contract is just a coincidence," Ciabatti said.
"Last year Jorge [Lorenzo] started winning on the Ducati after deciding to switch manufacturers, so I think it's just a coincidence.
"Danilo started the season in a perfect way and then he had three podiums in sequence, winning a fantastic race in Mugello. He also did a good race I would say in Sachsenring [right after the renewal].
"But after the summer break something changed and obviously we are trying to work with him, trying to give him back the same level of confidence he had in the first part of the season - so far, without success."
Petrucci's campaign worsened late on in 2019 as he failed to break into the top eight in any of the last seven races.
He called a meeting with Ducati staff after a particularly poor outing at Aragon, but he was unable to rediscover his early-season form.
Petrucci was also hindered by minor injury problems.
"Obviously we know he has some peculiar riding style, mainly because of his size and weight," Ciabatti said.
"So in certain conditions, he is suffering more than other riders with tyre wear. We struggle in general when there is a low level of grip.
"Anyway, we think Danilo is a rider who is capable of fighting for podiums and winning races, we just need to work with him and try to bring him back to what he showed he was able to do at the beginning of the season.
"So, we have confidence in him and we will work with him also for next year to bring him back to where he was in the first part of 2019."