Team principal Christian Horner claims Red Bull have "plenty of options" as they wait for a decision from Daniel Ricciardo on his long-term future.
Ricciardo's contract with Red Bull expires at the end of the season, although Horner has repeatedly spoken of his desire to keep the 28-year-old, while team consultant Helmut Marko revealed on Thursday that a "deadline" has been set for talks on a new deal.
Horner, speaking on Friday, would not be drawn on a timeframe for that decision, though, and hinted that Red Bull would have no issue with looking to another driver.
"Daniel needs to make sure that he's comfortable and he's making the right decision for next year," Horner told Sky Sports.
"From our perspective, we've got plenty of options. Our desire is to continue with Daniel and, at the right moment in time, there'll be an opportune moment to sit down and discuss the future with him.
"It feels a bit early at this point in time."
— Red Bull Racing (@redbullracing) March 9, 2018
Red Bull have been tipped to challenge for the constructors' championship this season, but Horner insists Mercedes – winners in each of the last four years – remain heavy favourites.
"It's so hard to draw conclusions – you get a bit of a flavour," he said. "Mercedes are in great shape, Ferrari are looking strong. We hope we're there or thereabouts.
"It'll be great for Formula One if there's a few teams in contention this year. But Mercedes are definitely going into this championship as very much the favourites."