Rosberg took the early lead in the title battle, opening the season with four back-to-back wins to open up a 43 point lead in the standings, but a mid-season fightback from Hamilton saw the Briton reverse that situation and go 19 points ahead.
Now three back-to-back wins for Rosberg at Spa, Monza and Singapore have put him back in control, opening up an eight point lead with six races remaining in this year's championship, and Ricciardo has said he believes that Rosberg now has the advantage and is set to him his first title.
"Before the summer break when Lewis made up that deficit on Nico, I thought no one was going to touch Lewis, but Nico has come back," the Red Bull driver told Sky Sports F1 during a trip to Australia.
Asked who he thought which of the Mercedes drivers would emerge on top at the end of the year, Ricciardo replied: "I'm going to throw a spanner in the works and say Rosberg."
By contrast, Hamilton was the choice of Jenson Button when he was asked recently who he thought would be crowned champion in 2016.
Rosberg and Hamilton have been on the podium together eight times so far, and Ricciardo has joined them on three of those occasions.
"The best part is if you get on the podium with them two, in the room before we go out on the podium just after the race, you take the helmet off and it's awkward for me because it's just so silent!
"I don't like silence too much, so I'm like trying to either talk to myself or make conversation with them but they are just happy enjoying the awkward silence. It's quite fun."