Sergio Perez, Bottas’s teammate, in the Cadillac MAC-26 during Italian Grand Prix qualifying. Photo: Eustace Bagge, Wikimedia Commons (CC BY 4.0)
Sergio Pérez’s 300th Grand Prix, at his home race, will get the attention this week, and deservedly. The more revealing line in Cadillac’s Mexico City preview sits further down: Colton Herta will drive Valtteri Bottas’s car in Friday’s first practice session, his fifth outing in that role for the team.
Cadillac announced four of those Friday runs in April. Mexico is a fifth by the team’s own count. My argument is that this is a choice, not an obligation. Cadillac is treating FP1 as a development hour aimed at 2027, and at the circuit where an hour of practice is hardest to spare, it is Bottas who covers the cost.
What the rule asks, and what Cadillac is doing
Section B of the FIA’s 2026 sporting regulations requires each car to be handed, in two Competitions, to a driver with no more than two Championship races behind him. For a two-car team, that is four sessions. Our explainer on how F1 gives rookie drivers practice sessions covers the mechanics.
Cadillac’s April announcement called Herta’s program four “young driver” sessions, and its Austin report counted his run at COTA as the fourth. Mexico is number five. Nothing in the rules caps it, and there is nothing improper about it. But teams don’t volunteer a spare session for a rule they regard as paperwork.
Why Mexico is the expensive one
Cadillac’s own preview lays out the problem. The Autódromo Hermanos Rodríguez sits at 2,240 metres, where air density is roughly 75 to 80 per cent of sea level. Cars need maximum cooling and maximum-downforce bodywork, and still reach straight-line speeds comparable to low-drag setups elsewhere. Bottas described a track with very little grip where small mistakes are punished.
In my view, that is exactly the profile of a weekend where you want your regular drivers in the car for the first hour. Cooling baselines and downforce levels are what you settle early. And there is no slack in the schedule: this is a standard weekend with no sprint, so after FP1 on Friday (12:30 local), the cars get FP2 at 16:00 and FP3 on Saturday at 11:30 before qualifying at 15:00. Hand FP1 to Herta, and Bottas has two practice hours to learn the circuit and find a balance.
Who gains, who pays
Pérez gains. At Austin, Herta drove his MAC-26 in FP1. At Mexico, on his 300th start in front of his home crowd, he keeps his Friday hour. Cadillac has not said that is why Bottas’s car was chosen, and I wouldn’t present it as fact, but it is a tidy outcome for a team that built its Mexico week around a Pérez show run on the Paseo de la Reforma.
Bottas pays. He retired at COTA on lap 48 with a suspected power-unit problem the team had not yet diagnosed, and he now loses an hour at a circuit where, per Cadillac, he took pole position in 2021 and still holds the race lap record. If his knowledge of this track is an asset, the team is choosing not to use it at 12:30 on Friday.
What Cadillac gets is a driver who can run a set program. At COTA, Herta did 20 laps, finished FP1 in 21st, and ended up 0.926 seconds off Bottas’s best in the other car, according to the team’s report. The team said he completed its test program. That is useful comparison data. The risk is just as obvious: a driver with no Grand Prix starts on a slippery circuit, in a car that has to qualify on Saturday.
What to watch
Team Principal Marcin Budkowski said the weekend’s demands “will further our learning” with 2027 in view. Watch whether Cadillac’s Friday looks like data collection: Herta’s run set against Pérez’s FP1 and Bottas’s FP2. The 2027 driver line-up is also still unconfirmed, and Budkowski declined to discuss contracts in Austin, as we reported from the official FIA transcript. That is context, not evidence. Nothing in Cadillac’s material says Herta is under consideration for a race seat.
At the front of the field, the story is Kimi Antonelli’s title push. At the back, Cadillac is betting the data is worth more than Bottas’s Friday hour. By Saturday afternoon we will have a better idea whether that was cheap.
Lead image: Sergio Pérez in the Cadillac MAC-26 during qualifying for the 2026 Italian Grand Prix. Photo: Eustace Bagge, Wikimedia Commons (CC BY 4.0)
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