Tsunoda has emerged as a candidate to replace the under fire and underperforming Sergio Perez for 2025.
The Japanese driver was not considered a viable alternative until recently, for reasons he himself was unclear of.
Perez’s prolonged slump is a significant concern for Red Bull Racing with his lack of contribution likely to see the team slip to third in the constructors’ championship.
That comes with a significant financial penalty with the sport’s prize money paid out based on finishing position in the teams’ competition.
Perez has a contract for 2025, and Horner has supported the embattled 34-year-old, though that stopped short of confirming he would remain in the car next season.
“It’s been a bad year for Checo,” the Red Bull Racing boss admitted.
“He started strongly and obviously he’s struggled for form since pretty much Imola onwards.
“It’s been sporadic. We saw flashes of performance, Azerbaijan, arguably he could have won that race almost a month ago.
“So we know what he’s capable of and we’re hoping that we can give him a set-up and the confidence in the car to extract the kind of performances that we know he’s very capable of.
“Checo’s our driver. He’s contracted for 2025,” Horner added.
“He’s competitive. He’s hungry. He’s not happy with where he currently is.
“As a team, we’re doing our very best to support him.”
Liam Lawson’s mid-season promotion in favour of Daniel Ricciardo has been viewed as offering the New Zealander an opportunity to make his case for the Red Bull Racing seat next season.
He recently completed a Pirelli tyre test for the senior team at Mugello (one of a handful of such outings in recent months), logging over 100 laps in an outing that also afforded the team an opportunity to assess him more closely.
Tsunoda is now set to be given a similar opportunity with Horner confirming he’ll drive for Red Bull Racing at the end of season test in Abu Dhabi.
“Yuki, obviously, again, is a member of the junior team,” Horner said.
“It’s something that we have discussed with Honda.
“It’s something that’s been agreed for quite some time and it will again be good to give him a run and get the opportunity to work with Red Bull Racing engineers and see how he performs in a Red Bull Racing car.”
The post-season test sees team field two cars, one with an established race driver and another with a ‘young’ driver.
With Tsunoda at Red Bull Racing essentially fulfilling the role of the latter, it suggests Isack Hadjar will pilot the other car.
For the purposes of the test, Lawson is no longer considered a young driver and is instead expected to remain with RB for the outing.
Who joins him remains unclear with Arvid Lindblad arguably next in line in the Red Bull program.
However, the 17-year-old is only set to graduate to Formula 2 for 2025 and, therefore, a year away from being ready for F1 consideration.
That could see Ayumu Iwasa called into action, having been campaigning in Super Formula this season, or F2 racer Pepe Marti.
The post-season test takes place on the Tuesday following the Abu Dhabi Grand Prix.