When Ricciardo broke a metacarpal in his left hand in a practice crash at Zandvoort, Horner initially suggested that the Australian was targeting a return for the Qatar round last weekend.
But on the Monday ahead of the race, Ricciardo video called his substitute Liam Lawson to tell the Kiwi he would be required one last time before returning in the United States GP.
Horner says Ricciardo was right to delay his comeback as the extreme, humid Qatari conditions left drivers throwing up, partially losing their vision and being diagnosed with acute dehydration.
“I think we want to see him in full fitness”, Horner said of the eight-time GP winner. “I think it was right to miss this race, particularly as it turned out with the conditions that we had.
“Austin [the next round], obviously it's going to be difficult for him to jump straight back into a sprint race weekend but I'm sure he'll be physically in good shape to take that on.”
AlphaTauri has maintained throughout that Ricciardo would be the one to decide when he should come back. The Australian only returned to front-line F1 duty in Hungary to replace the sacked Nyck de Vries following a stint on the sidelines after parting ways with McLaren.
Ricciardo has, however, already returned to extensive simulator duty and was approaching full race distances with minimal distress.
Horner alluded to having to dissuade Ricciardo from making a premature comeback.
He continued: “Of course, he was wanting to come back but he has a contract secured for next year [with AlphaTauri] and in Liam, we've got such a great sub.
“It was also a good way of giving him another grand prix without actually putting unnecessary pressure and potential longer-term damage on Dan to say, ‘Look, don't overstretch it’.
“As it turned out, the conditions that we have here could have been very testing for him.
“To have had that extra 12 days in the run-up to Austin is the best preparation.”
