Jorge Lorenzo is an unknown quantity for the 2017 MotoGP season following his move to Ducati, according to world champion Marc Marquez.
Since Marquez's rise to MotoGP in 2013 the pair have battled it out for the riders' title, the Repsol Honda rider winning it on three occasions and Lorenzo taking the other.
Last season there was little to choose between the two Spaniards in the early rounds before Marquez pulled away in the middle section of the campaign.
As Marquez celebrated the third championship of his career, Lorenzo announced he was to leave Yamaha and sign for Ducati.
Marquez knows the threat his rival poses but acknowledges their competitiveness remains uncertain ahead of the opening race in Qatar on March 26.
"More or less [it will be] the same riders as every year [to fight for the title]," he said, as quoted by Crash.net.
"[Valentino] Rossi, [Maverick] Vinales and [Dani] Pedrosa – who has had a very consistent pre-season.
"We'll see with Lorenzo, because he can have good races and the mystery is whether he can be fighting for the podium every Sunday, which will indicate if he can aspire to win the World Championship."
While Marquez may be unsure, Ducati technical chief Gigi Dall'Igna does not expect his team to be pushing for race wins with Lorenzo and team-mate Andrea Dovizioso.
"Our goal after signing Jorge is to fight for the world championship," Dall'Igna told Movistar.
"It's clear that at the moment we are not ready to do it, but we do have solutions to reduce the problems we have.
"We are satisfied with Dovizioso's development work this pre-season.
"In the case of Jorge, there is still a lot of work to do, but I'm happy with what we have done together."