“We do have a legal contract with him (Piastri) into the future for ’23. And if an option is taken up, for ’24,” he said.
“I don’t know what he’s done with McLaren … I’m not privy to that.”
Piastri had previously been linked to Williams, but that was as a loan deal on the understanding that he would return to Alpine when Alonso left.
There was no comment from McLaren, who are battling Alpine for fourth place in the constructors’ championship, and Piastri’s management could not be contacted immediately.
McLaren have Daniel Ricciardo and Britain’s Lando Norris but the experienced Australian has been performing below expectations and his place called into question.
Ricciardo, who joined McLaren from the Renault team that is now Alpine, has insisted he is staying and has an option on his side.
Formula 1 has a contracts recognition board to settle disputes between teams over drivers and the matter could end up there.
Alpine, as part of a major manufacturer, are unlikely to have taken the step of announcing a driver without feeling confident, however.
“We believe we are legally correct in our statement,” the team said, without further comment.
There was an air of uncertainty and mis-communication, however, with Szafnauer saying he found out about Alonso’s move only when he read Aston Martin’s press release.
Asked whether he had spoken to Alonso, Szafnauer replied: “I haven’t talked to him, since he’s on a boat, I think, in the Greek Isles somewhere.”
Alonso then posted on Instagram a video of himself walking in his home town of Oviedo in northern Spain. He also tweeted a picture of a go-kart at his museum track with the caption “favorite activity on holidays”.
The dispute echoes another ongoing contract clash between McLaren and Chip Ganassi Racing in IndyCar over reigning champion Alex Palou.
Spaniard Palou announced last month that he will be joining McLaren’s roster of drivers for 2023, hours after Ganassi said he was staying with them.
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