By Alan Baldwin
MONACO, May 28 (Reuters) - Daniel Ricciardo's stock has never been higher after a dominant Monaco Grand Prix weekend that saw him stand on the podium above two world champions whose 2019 team mates have yet to be confirmed.
The Australian is out of contract with Red Bull at the end of the season and champions Mercedes or Ferrari (NYSE:RACE), the top two teams, are obvious possible alternatives.
Ferrari's Sebastian Vettel was second in Monaco with championship leader Lewis Hamilton third for Mercedes but Ricciardo led every single practice and qualifying session and throughout the race.
Red Bull also want the 28-year-old to stay, but will be expected to pay a lot more than at present given Ricciardo's success.
"You could say the day's maybe made Daniel more expensive, it's put his value up," Red Bull principal Christian Horner told reporters.
"Or you could say it's put the team in a stronger position in terms of its value and potential to him."
Ricciardo has won two races this year, the same number as Vettel and Hamilton, and is third overall -- albeit 38 points behind Britain's Hamilton.
The Australian would be a lot closer had he not retired early on with an electrical problem in Bahrain and been in a collision with team mate Max Verstappen in Azerbaijan.
Verstappen, 20, is on a lucrative long-term contract but has had a season full of mistakes and crashes.
Horner hoped a new deal with Ricciardo could be reached "in the next couple of months" but recognised much would depend on what engine Red Bull had next season.
The former champions use Renault (PA:RENA) power units but have been linked to Honda, now with Red Bull-owned Toro Rosso.
Honda's engines have improved considerably after three dismal years with McLaren, and France's Pierre Gasly finished seventh for Toro Rosso on Sunday.
Mercedes say they are not looking beyond their immediate "family" at present, with Finland's Valtteri Bottas performing well as Hamilton's team mate, and Ferrari could retain veteran Kimi Raikkonen.
While Ricciardo would be popular, as a driver of Italian extraction with a reputation for thrilling overtakes, Ferrari also see Sauber's 20-year-old Charles Leclerc as a longer-term option.
Whatever the reality, Ricciardo is putting himself front, side and centre in the shop window, knowing that any interest adds to his bargaining power.
"We'll see what the others think. I can't pay myself but for sure I feel I've done a really good job in the first six races," he said.