Lewis Hamilton has poured cold water on Daniel Ricciardo's hopes of moving to Mercedes.
Ricciardo's value has never been higher after he delivered the most dominant weekend of his Grand Prix career in Monaco.
The Australian topped every practice and qualifying session in Monte Carlo before nursing his wounded Red Bull over the line for his second victory of the campaign.
Ricciardo, whose contract is up for renewal, moved ahead of Mercedes' Valtteri Bottas in the standings and to within 38 points of Hamilton.
The 28-year-old has spoken of his desire to team up with Hamilton.
Bottas and Ferrari's Kimi Raikkonen could yet be moved on at the end of the season, but Hamilton believes Ricciardo might have to extend his stay.
"I would imagine his future is at Red Bull," Hamilton said. "He is one of the top drivers, so I'm sure there will be options for him, and it is only Ferrari and Mercedes among the top teams that he could consider.
"But currently here at this team that is unlikely and I don't think that (Ricciardo joining Mercedes) is going to happen."
Red Bull vowed to build their team around Max Verstappen after tying him to a long-term contract, estimated to be worth as much as £20million-a-year, at the end of last season.
But Ricciardo's form, coupled with the 20-year-old Verstappen's error-prone campaign, has seen him emerge as the team's number one contender.