Horner: Ricciardo could miss Singapore and Japan

The 34-year-old Australian suffered the injury in practice for last month's Dutch Grand Prix and had surgery in Spain on 27 August.

New Zealander Liam Lawson replaced Ricciardo at the Red Bull-owned sister Formula 1 team at Zandvoort and in the Italian Grand Prix at Monza last weekend.

"Certainly Singapore, I don't think there's any chance he (Ricciardo) will be ready for then. It would be optimistic for Japan," Horner told reporters after the race at Monza.

"But I think his recovery is going well, he's got obviously mobility of the hand and he's into rehabilitation now," he revealed.

"We've seen with motorcyclists rushing comebacks, they sometimes do more damage so I think we just want to make sure he's fully fit before he gets back in the car."

Lawson was racing in Japan's Super Formula before being called up to replace Ricciardo, and when asked if the Kiwi would be keen to race an F1 car at Suzuka, Horner said: "I think he's pretty keen to be in the car in Suzuka.

"But we just take it on a day-by-day basis and, and see how the recovery and nature takes its course," the Red Bull boss insisted.

Horner said Lawson, who has been racing in Japan this year and would undoubtedly feel at home at Suzuka, had done a solid job: "I think he's acquitted himself very well."

Lawson finished 11th at Monza after 13th place in the Netherlands.