Hamilton's shock decision to leave Mercedes has energised the driver market ahead of 2025, just when it appeared to be stalling as Ferrari and McLaren moved to tie Charles Leclerc and Lando Norris to long-term deals.
World champion Max Verstappen is contracted to Red Bull until the end of the 2028 season.
Hamilton's impending move means Mercedes is suddenly in need of a replacement to race alongside George Russell next season, with its options limited by the timing of Hamilton's decision and those new contracts being issued for desirable drivers at other teams.
Bottas is entering what he calls a "contract year" with Sauber – ahead of its Audi takeover for 2026 – where he has raced since being replaced as Hamilton's Mercedes team-mate by Russell ahead of the 2022 campaign.
When asked to give his reaction to the Hamilton/Ferrari news at Sauber's 2024 car launch at London's historic Guildhall on Monday, the Finn said he was "surprised" by the development as he "never actually thought that could happen".
He added: "But I think it's good for him – it's a big opportunity, it's a big move. And obviously he's made the decision himself.
"Yeah, [I'm] happy for him and for sure that's now going to escalate some movement in the market for 2025. So, at the moment, it's quite hard to predict how it's going to go.
"I never imagined it would happen. And also the timing of it. But I'm happy for him because it's good for him.
Source: Autosport