"The decision's made. We all know who it is. I'm happy with that decision. It's good for him and good for Australia," Webber told Australia's Channel 10 television at the Belgian Grand Prix.
Ricciardo, the only other Australian in F1, is already under contract with Red Bull as a driver with their sister team Toro Rosso but told reporters he had yet to hear anything from the champions.
Asked about Webber's words, Red Bull principal Christian Horner told reporters nothing had been decided and an announcement would probably not come until after the Italian Grand Prix on Sept. 8.
"There's plenty of speculation about, but nothing has been signed yet," he said.
"Comments get taken out of context sometimes. Mark obviously isn't privy to all the discussions with drivers. When there's something to announce, we'll announce it."
Webber, who finished fifth in the race won by triple champion team mate Sebastian Vettel, is leaving Formula One at the end of the season for a future in Le Mans sportscar racing with Porsche.
Horner said the fact Ricciardo was already under contract meant they could take time assessing other options.
"Both Toro Rosso drivers are on Red Bull Racing contracts," he explained. "They are on loan to Toro Rosso. So at any point they are available for us to call upon.
"So we don't have to worry about those two...the reason that we have taken the time is to look at what other options are about because they are obviously very big shoes to fill with Mark (gone) next year.
"It's absolutely prudent to look at all the options that are available. It's actually surprised us (to hear) the options that are available and that perhaps we didn't think were."
Lotus's Kimi Raikkonen and Ferrari's Fernando Alonso have both been linked to Red Bull in paddock speculation.