Hamilton only signed a fresh two-year deal with Mercedes for 2024 and 2025 last summer, but clearly left wiggle room for the usual exit clauses in case he had a change of heart.
And as Ferrari confirmed Charles Leclerc's new contract but dragged its feet over giving Carlos Sainz a similar extension, it turns out Hamilton being on the table has made the Scuderia think twice over its future driver line-up.
With Leclerc and Hamilton both former proteges of team boss Fred Vasseur, while Sainz was seen as a Mattia Binotto hire, Ferrari's driver line-up now looks well poised for Maranello's bid to topple Red Bull. But it has also left a hole at Mercedes at a most inconvenient time.
Had Hamilton's move been rubber-stamped any earlier, Mercedes may have had more options to play with on the driver market. But Hamilton's impending switch has been preceded by several high-profile contract renewals that took key pieces off the board.
Leclerc, who is set to partner the seven-time world champion from 2025 onwards, would presumably have been a key target for the Silver Arrows. And with Max Verstappen firmly locked in at Red Bull, there aren't too many other proven names that are available in 2025.
Mercedes would have had a good look at McLaren's pairing Lando Norris and Oscar Piastri, but after the Australian extended last year Norris also recently put pen to paper on a deal that will keep him at McLaren for 2026 and possibly beyond.
So, who else could Mercedes move for?
There was initial excitement on social media about Mercedes' prodigy Andrea Kimi Antonelli, who is debuting in Formula 2 this year after being fast-tracked through the junior ladder following a single, championship winning season in FRECA.
But even if there is a precedent in F1 with Kimi Raikkonen and Verstappen, promoting the now 17-year-old after just three years in cars seems fanciful and against Mercedes' previous young driver policy.
Following his F2 title George Russell was farmed out to Williams for three seasons of learning the ropes before re-joining his parent team. And even if Antonelli delivers on his promise in F2 right away, a similar move might be more beneficial for the starlet's long-term career.
So, if Russell-Antonelli is seen as Mercedes' future, then who could be a stop-gap signing for at least 2025 and 2026?
If there is one free agent whose stock has risen in recent years, it has to be Williams' Alex Albon. Now a much stronger driver than when he was burnt by an early promotion to Red Bull, Albon has played an instrumental role in the Williams recovery process.
He scored all but one of the team's 28 points in 2023 to drag the team up from 10th to seventh in the constructors' championship, and has been praised for his blossoming leadership qualities.
Aged 27 and coming off the back of his strongest ever season in F1, Albon's blend of speed and maturity would make him an astute signing. Russell and Albon's long-time friendship should on paper help provide Mercedes with a harmonious pairing.
When asked by Autosport last year about his expiring deal, Albon said: "I think I have the confidence in myself to keep myself open.
"Being totally honest, I want to see this team and I want to be part of a team that brings this team forward. I'm fully committed to the team until my contract pretty much ends.
"But I am also 27 and I do feel like I am in a good part of my career. If you take another year I'm 28, then 29 going onto 30 soon.
"I want to give myself the chance to be able to fight for wins and fight for podiums. And what it comes down to is, at that time and in that time, can we bring this team to be that team?"
Another safe pair of hands, with race winning credentials no less, is the obvious swap of Hamilton with the driver he replaces, Carlos Sainz.
Sainz has traded blows with Ferrari team-mate Leclerc quite evenly in 2023, with both drivers enjoying dominant spells before ending on a similar points tally. The Spaniard's cunning victory Singapore, gifting Ferrari the only non-Red Bull win of the year, has also underlined his racing intelligence that would make him a pragmatic asset to Mercedes or any other squad.
As the dust from Hamilton's sensational move settles, Sainz's manager will likely be on the phone to Mercedes chief Toto Wolff about making it a straight swap.
A third, perhaps less likely, option would rekindle Wolff's relationship with one of his other former proteges. Before Russell was earmarked as Hamilton's heir, Esteban Ocon was Wolff's and Mercedes' main man for the future.
And while the Frenchman found his feet with first Manor and then Force India/Racing Point, Ocon acted as Brackley's reserve driver until he left the Mercedes family by signing with Renault, now Alpine.
It is not entirely clear how high Ocon's stock still is at Brackley, but at the same age as Albon and with an impressive race win in Hungary on his belt, Ocon provides a similar blend of youth and experience that might entice Mercedes, at least until Antonelli is ready.
Out of the free agent options, the most remarkable signing would be two-time world champion Fernando Alonso, who will also be out of contract at Aston Martin after showing he has lost nothing of his ability in a remarkable 2023 campaign with eight podiums.
Replacing one world champion with another could be a fascinating prospect for Mercedes, even as Alonso will be 43 at the start of the 2025 season.
But Hamilton's move is a stark reminder that F1 contracts are often not as watertight as they seem. Perhaps Mercedes might yet find a way to entice a big name and cause a transfer shock of its own.
