Fernando Alonso ruled out taking over countryman Oriol Servia's seat in the Indy 500 because it was "unethical".

That is not the claim of Alonso, or his boss Zak Brown, but of Spaniard Servia himself.

The seat occupied by Servia, 44, was targeted by McLaren boss Zak Brown under a system whereby places on the grid can be "bought" by those who do not qualify.

When Brown told Alonso that Servia's car was a possibility, Alonso called the driver himself.

"I spoke with Fernando the same night the question was raised," Servia told El Mundo Deportivo.

"He called me and was super transparent. He asked me what I thought and I told him that obviously I would not like it if someone took my seat, but that I knew it was not personal and that I would do what I had to do.

"To him, it seemed unethical to take my seat, or the seat of anyone who qualified. It is just another detail that demonstrates his class," he added.

"I would have understood if he sat in another car because McLaren wanted him too and he would have tried to win the triple crown. But he showed ethics and morals," Servia said.

Servia said Alonso was actually "amazed" that the seat-buying possibility existed in the world of Indycar. "He told me 'They're crazy!'

"When a team like McLaren arrives and says 'we're McLaren and we're here to show you what we can do', I think it's pretty ugly if you buy the place," he added.

Servia says he hopes Alonso tries again in 2020 or beyond.

"I hope he does, with or without McLaren," he said. "If it's McLaren, they'll come back prepared. And if not, he can sit in any other car that he wants.

"I think what happened with McLaren was that they focused too much on Formula 1. Miracles do not happen and they arrived here too unprepared."