Ducati sporting director Paolo Ciabatti has strongly dismissed speculation Jack Miller was under consideration to replace Danilo Petrucci for 2020, insisting they never discussed making a change.
Petrucci started the 2019 season brightly, including recording a victory at the Italian Grand Prix, but his form tailed off badly.
Having retired in two of the final three races in the campaign, the Italian was rumoured to be in danger of losing his Ducati spot to Miller, despite finishing ahead of him in the final standings.
The Australian had impressed with Pramac Racing, recording podium finishes at Phillip Island and also the season-ending race in Valencia.
Asked about a potential change in the Ducati line-up following Tuesday's testing session, Ciabatti said: "Can I say something that won't sound very nice - b******t!
"We never spoke about this; this came out in the paddock, somebody had this idea, but we never had any idea to make any changes to the factory team or the Pramac team."
There have also been rumours over Johann Zarco joining Avintia Ducati, with Ciabatti confirming he has held discussions with the Frenchman over his future.
"We had a conversation with Johann yesterday [Monday] to understand his position. He has an option to go back to Moto2 with the Marc VDS team, so I think we will understand more in the next few days," he said, according to MotoGP.com.
"I think that to know what's going to happen next year, it's good to make a decision about them pretty soon, so we can take the next steps."
Zarco has the option of taking up a testing role with Yamaha, as confirmed by their team principal, Lin Jarvis.
"I spoke to Johann 10 days ago and said to him that if his Honda programme didn't work out, then we're still open to consider him being a test rider for us," Jarvis said.
"He's expressed an interest to stay racing, so I think the first thing he needs to decide is if he wants to stay racing or, is he interested in testing and that’s really up to him."
Meanwhile, on the track in Valencia, Fabio Quartararo was fastest in the testing session, despite a heavy crash. There were also falls for brothers Alex and Marc Marquez, the latter making a mess of his new Honda at Turn 13.