However, Horner, his fellow Red Bull official Dr Helmut Marko, Toro Rosso's Franz Tost and Renault boss Cyril Abiteboul have all denied that Sainz switching to replace the struggling Jolyon Palmer at Renault will be complete by Hungary.
Now, Sainz is also playing down that scenario.
As for the Renault switch rumours, Sainz continued: "Yes, many people are asking me to comment on these rumours.
"For me, it's just speculation, and I do not comment on that."
He denied that the recent controversy in Austria, where his Red Bull chiefs scolded him for comments in the media, had damaged the relationship irreparably.
"After Austria we all made clear that what was said was misunderstood," said Sainz.
"At Silverstone I was playing tennis with Christian Horner, and Helmut was the umpire. We had a great time and everything between us is all in order now.
"I am a Red Bull driver, taking part in the youth programme of the company and I am sure that I will stay at Toro Rosso next year, trying to deal with the problems starting with the Hungarian grand prix," he added.
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