Ricciardo was ousted from his drive at RB following the Singapore Grand Prix and will replaced for the balance of the season by 22-year-old New Zealander Liam Lawson.
The change is partly driven by performance, with Ricciardo having endured patchy form since returning mid-season last year, but also with a view to the future.
Speaking on the F1 Nation podcast, Horner admitted he would have ideally left the Australian in the car for the remainder of the year, but other influences were at play.
“From a broader perspective we need answers for the bigger picture in terms of drivers,” he admitted.
“With six races remaining, it’s the perfect opportunity to line Liam up alongside Yuki [Tsunoda], to see how he performs.
“This goes beyond VCARB, it encompasses Red Bull Racing,” he added.
“We have a contract with Sergio [Perez] for next year, but you’ve always got to have an eye out in terms of what comes next; is that going to be Liam, or do we need to look outside the pool? Or will one of the other juniors step up in the fullness of time, whether that’s Isack Hadjar or Arvid Lindblad?”
By replacing Ricciardo now, Horner has the opportunity to assess Lawson over the coming six races.
His confirmation announcement referenced only his 2024 season, not where he would be driving in 2025.
The suggestion is that, should Perez fail to fire and Lawson shine, the Kiwi could find himself alongside Max Verstappen at Red Bull Racing next season.
That in turn opens an opportunity for Hadjar a year earlier than would have otherwise been the case, and eases the pressure on RB come 2026 should Lindblad prove ready as it would not have two all-new drivers to F1.
Six races equates to a quarter of the 2024 season, though Horner admitted there was pressure to give Lawson much more seat time as Ricciardo struggled to meet expectations even before the halfway point of the campaign.
“I think it was the lack of consistency,” Horner admitted of his concern regarding Ricciardo’s performances.
“He started the season roughly, then Miami was a weekend of two halves; the Friday and Saturday morning was fantastic and it looked like the Daniel of old, defending against Ferraris, out-driving the car, but then Saturday afternoon and the Sunday were disastrous.
“Even around Barcelona, Helmut [Marko, Red Bull motorsport advisor] wanted him out of the car.
“There was already a lot of pressure on him there, but by the time we got to Montreal it was actually dear old Jacques Villeneuve who got him properly wound up by giving him a hard time.
“It definitely fired him up because the way he drove the car that weekend, he grabbed it by the scruff of the neck and put together a very strong race weekend, so I did say give Jacques a call every grand prix for the rest of the year because whatever he said it definitely worked!”
Horner was and remains a firm supporter of Ricciardo. Speedcafe understands it was Horner who was responsible for his F1 return, giving Ricciardo the drive in place of Nyck de Vries despite it being promised to Lawson.
This year, Horner worked to protect the Australian as best he could, but ultimately the tide proved too strong.
“I’ve done my very best to buy him as much time in the car to allow him to deliver, so otherwise he would have been out of the car after Barcelona,” Horner revealed.
“All the drivers are under pressure to deliver but the reason that Daniel was in that car was to get himself back into a position to ultimately be there to pick up the pieces if Checo didn’t deliver.
“The problem was, they both had issues with form at varying times.
“Checo started the season very well, very strongly, and Daniel was struggling.
“Then, as Checo lost form, Daniel found a bit of form but it was never compelling enough to say okay we should switch the two drivers.”
Ultimately it didn’t pan out and when the opportunity to replace Perez presented itself, Ricciardo was overlooked.
At that point, his warrant was effectively signed.
“I would have loved to see him use it as a springboard to get back to where he was, to have completed the story, but it wasn’t to be,” Horner reflected.
“Daniel’s honest about that, and he knows in his heart he gave it his best shot.
“He’s had a great career, he’s had a great run, but unfortunately the next chapter wasn’t to be.”
There has been an offer for Ricciardo to remain in the Red Bull family, working as an ambassador with the brand in much the way David Coulthard has since his F1 retirement.
“He’s so good in front of the camera,” Horner reasoned.
“He’s a natural entertainer and a showman, he will be for sure in front of the camera at some point and I’m sure there will be a documentary or something, that will be fascinating.”