We've reached January and for football fans that means one thing - the winter transfer window is now open. 

The headlines will no doubt be dominated by the likes of Jadon Sancho, Paul Pogba and Gareth Bale.   

But as well as big-money moves, there's also the possibility that some top players could transfer for free. 

Plenty of stars are entering the final six months of their deals, meaning they can sign pre-contracts with a new club and move for free at the end of the season. 

This January, there are some massive names that can move on a free transfer - check them out below. 

Luka Modric 

Imagine if the 2018 Ballon d'Or winner leaves Real Madrid for free. Well, it's a possibility.

The form of youngster Federico Valverde is starting to push Modric out of the team and the 34-year-old could decide to leave Los Blancos in six months.

Despite his age, the midfielder would still improve almost any team in Europe. 

Christian Eriksen

The saga continues. Eriksen has been linked with a move away from Tottenham for the last couple of years now. 

He's showing no sign of agreeing on a new deal and looks set for a new challenge next season. Spurs will be disappointed not to make any money from his move, though. 

Mario Gotze

Gotze's career peaked at a young age. At 22, he scored the winning goal for Germany in the World Cup final. But the last five years have been pretty rocky for the midfielder. 

He's only 27 and has bags of talent, but after being diagnosed with a muscular disorder, he could soon be set to leave Borussia Dortmund. 

Edinson Cavani

Cavani has scored 196 goals in 289 appearances for Paris Saint-Germain. But he's now 32 and has to compete with Neymar, Kylian Mbappe and Mauro Icardi for a starting place in the XI.

Reports suggest he's going to join Atletico Madrid and if the Spanish side wait six months, he'll go for free. 

Thiago Silva

Another PSG star that's out of contract is Brazilian defender Silva. He was one of the best centre-backs in Europe over the last decade, but now 35, he probably won't be signing a new deal. 

He's still got time for one more big move, though. 

Willian

Chelsea's Brazilian winger has been impressive this season. But Willian doesn't exactly fit Frank Lampard's philosophy. 

Barcelona have been heavily linked with making a move in recent years and could finally get their man on a free transfer. 

Ryan Fraser

Fraser has previously been linked with moves to both Liverpool and Arsenal.

He's one of Bournemouth's key players but is continuing to 'keep his options open' by not committing to the Cherries. It may finally be time to move on next summer. 

Dries Mertens

Reports suggest that Mertens is unsettled at Napoli this season. Arsenal, Bayern Munich and Borussia Dortmund are interested and the Italian club would be willing to sell for £8.5m. 

But wait six months, and he could move for free. 

Eric Bailly

Bailly hasn't exactly established himself at Man United after making his £30m move in 2015.

He's been troubled by injury throughout his time at Old Trafford and now has tough competition at the back. United have the option to trigger a contract extension, but it's not clear yet if they will. 

Jan Vertonghen

One Spurs centre-back - Toby Alderweireld - recently committed his future to the club. But his partner is yet to sign a new deal. 

The Belgian is a top centre-back and Mourinho will no doubt want to keep his man, but the decision is now in Vertonghen's hands. 

There are some very big players coming to the ends of their contracts this year.

We'll have to wait and see how many will actually move on for free, but surely, the likes of Modric, Silva, Fraser and Eriksen will all be on the radars of top European clubs. 

It could be a very exciting January transfer window.