Double champion Alonso is among several drivers out of contract at the end of the season.
Verstappen has a contract with Red Bull until 2028 but his future has been clouded by a breakdown in relations between his father Jos and principal Christian Horner.
Asked whether Max's exit could impact his and other drivers' battle for seats at a press briefing at Suzuka Circuit ahead of the Japan Grand Prix, Alonso said:
"If Max leaves Red Bull maybe that has an impact but I think there's zero chance of that happening."
"What I want to do is just concentrate on my stuff...and before summer try to make a decision if I keep racing or not. And if I keep racing, where would be the best possibility," he said.
Mercedes boss Toto Wolff, who is losing seven-time champion Lewis Hamilton to Ferrari at the end of the season, has said Verstappen would be top of his list of possible replacements if he becomes available.
Wolff also mentioned Alonso, Ferrari's Carlos Sainz - the only non-Red Bull driver to win a race in the last two seasons - and Mercedes-backed F2 rookie Kimi Antonelli as possible options.
Verstappen repeated at a press conference on Thursday that he was "very happy" at Red Bull and said he was not thinking about future moves.
