Ricciardo was forced to watch his team-mate Max Verstappen hog the limelight after his stunning victory at the Mexico Grand Prix.
Despite being fourth in the championship standings, Ricciardo is in danger of being left behind by Verstappen, who has made huge strides on the circuit this season.
Ricciardo’s contract expires next year, and while Horner wants to retain his top driver, he says Carlos Sainz is still a contingency option.
“The next move he [Ricciardo] makes at 28 years of age is a very important one for him,” Horner told Reuters.
“So of course I’m sure he’s going to take the time to make sure the decision is right for him.
“But he knows the intent very clearly, and I’ve discussed it with him, is that we want him in the team. If that takes another six months, then so be it.
“He knows how we go about our racing and how we treat the two drivers, which he’s extremely comfortable and happy with.
“That’s why we kept Carlos [Sainz] on loan, that’s why we have options around us.
“We have a safety net but our number one objective is to retain the pairing that we have.”
The F1 heads to Sao Paulo next week for the Brazilian Grand Prix, the penultimate race of the season.
