The January transfer window will open in just a few hours. When midnight comes in the UK (4pm on the west coast of the US and 7pm on the east coast), Premier League sides will be officially able to make more transfers.

Liverpool manager Jürgen Klopp went out of his way to explain why that was unlikely at the start of the month, though Kostas Tsimikas has since been struck down with a broken collarbone. That leaves a lot of work for Joe Gomez to get through at left-back, and Jarell Quansah as the only covering player in the center for Virgil van Dijk and Ibrahima Konaté.

Looking beyond this month, however, there is another opportunity that could also arise transfer-wise. January 1 marks the date from which clubs abroad can negotiate pre-contract agreements for the summer with players that are set to become free agents.

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For Liverpool, Thiago Alcântara and Joël Matip are both in that position as things stand. Both see their current deals expire at the end of the season, meaning clubs outside of England can freely make contact during January about bringing them in over the summer.

But which players could Liverpool hypothetically contact? Liverpool.com has taken a look at the best options available on the market and had a look at who might be worth considering.

Kylian Mbappé is one player that will be coveted, and he has been linked with a move to Anfield on plenty of occasions. That has only ever been the tiniest bit realistic on a free, though the money involved would still be astronomical. Real Madrid is almost certainly the team that he will represent if he leaves PSG.

Piotr Zielinski, now 29, was a player that Liverpool made a bid for back in 2016, before eventually signing Gini Wijnaldum instead. Klopp was keen on the Polish playmaker but he stayed at Napoli, where his contract is running down.

Hoffenheim’s left-back Robert Skov was once on Liverpool and Tottenham’s radar but he never ended up leaving Germany. That could happen this summer, though, with his contract set to expire. Now 27, it will be interesting to see whether there is interest from England these days for a player who once stood out in the stats.

Lloyd Kelly is another that Klopp has looked at in the past. Now at Bournemouth, the left-sided defender has never hit the heights that would be required to make him a real long-term target for Liverpool. Tosin Adarabioyo at Fulham, also out of contract, fits into the same boat.

Neither are available to negotiate a free transfer with just yet as they are both with other Premier League sides. But could either be useful as cheap options in January to add some more depth at the back? There have been worse ideas put forward.

Boca Juniors wonderkid Valentín Barco is out of contract in 2024, but not until December, so no one can negotiate with him just yet. Brighton, Manchester City and Liverpool, according to Goal, are all taking a look at the young Argentina left-back.