It means the team will have to take an engine penalty at some point in the season, with Horner confirming on Sky Sports F1 such a decision would be strategic.
"I think we were glad to get to the summer break because we had five consecutive races which were fantastic," said Horner.
"Then we had Silverstone and Hungary that were very frustrating for us so to take a break was very useful and well-timed.
"Of course, we will have to take penalties later in the year and it is a question of strategically, when do we take those.
"I think we will wait to see exactly what the calendar evolution is looking like as well but you have got to pick your moments strategically to do that.
"Do you do it early or do it a bit later and pick a time that maybe you have a bad session and then that is the time to effect a change?"
Red Bull must be "flexible"
Red Bull had the option of introducing two new power units this weekend to take the penalty at a circuit that teams know offers overtaking opportunities.
With rain forecast throughout the weekend, Horner explained: "It is a good track in that it is an open circuit and you can overtake here.
"At the same time, if you have qualified well, do you want to be in the mist and spray and we saw the dangers of a damp race at the last weekend?
"It is something we are constantly evaluating and constantly looking at. As long as you are flexible with it, the right opportunity will present itself."
What do you think?
Two races are still "TBA" after cancellations. Three races, USA, Mexico, and Brazil, are doubtful given COVID and not just in those countries, but also for teams returning to the UK or other country. US isn't accepting visitors anyway.
F1 needs to sort out the rest of the races quickly. Either admit 23 races is ambitious in a pandemic and cut the season down (23 is already too much for the personnel in the teams to be honest - far too much travelling). And quickly find substitute races, but not Austria again as that gives an unfair advantage to Red Bull.
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