Where Erling Haaland's long-term future lies is anybody's guess, with the world's biggest clubs queueing up in a bid to prize him away from Borussia Dortmund.
Real Madrid are many people's favourites to land Haaland, even though they're likely to sign Kylian Mbappe from PSG, and reports in Spain suggest they may soon find out if he intends to join them – with Dortmund seeking a meeting with the Norwegian to clarify his plans.
Another player who has an uncertain future is Manchester United forward Anthony Martial. The Frenchman is down the pecking order at Old Trafford and is actively seeking a move away from the club in order to play regular first-team football. Sevilla have been linked with a possible loan move in the past, but it now seems they've accepted that paying his lofty wages is a non-runner.
Martial's teammate Eric Bailly is also the subject of interest from abroad, with AC Milan monitoring the Ivorian ahead of a potential bid. The 27-year-old is by no means first choice under Ralf Rangnick - a situation he's been accustomed to over the years - but may be lured to San Siro with the promise of more regular action.
Jesse Lingard continues to weigh up his options and remains unlikely to make a decision on his future this month. That's despite continued interest from West Ham, who he starred on loan at last season, and an enquiry from Tottenham - who are looking to bolster Antonio Conte's forward options ahead of an expected exit for Steven Bergwijn, potentially to Ajax.
Roma continue to flirt with the idea of bidding for Arsenal midfielder Granit Xhaka, with Jose Mourinho keen to bolster his options in the centre of the park. Struggling Tottenham star Tanguy Ndombele has also been linked with a move to Serie A, even though a deal for Porto's Sergio Oliveira is close.
Xhaka's Arsenal teammate Eddie Nketiah may also be heading for the Emirates Stadium exit in January, amid interest from Crystal Palace. A loan deal taking Folarin Balogun to Middlesbrough is also imminent subject to the player successfully completing a medical.
On Tyneside, business is picking up for Newcastle as they bid to strengthen their relegation-threatened squad. Chris Wood is on the verge of joining from Burnley in a deal worth £20m, while talks are ongoing with young Reims' striker Hugo Ekitike – though interest from Brighton, Brentford and a growing number of clubs is complicating matters.
One player who is unlikely be returning to the club on loan is Georginio Wijnaldum. The Dutchman isn't having a great time of it at Paris Saint-Germain, who he joined in the summer from Liverpool, but he's said to have no desire to return to St. James' Park.
PSG may have a big deal up their sleeve this summer in the women's game, though their interest in Arsenal's Vivianne Miedema is complicated by Women's Champions League holders Barcelona taking a look. It's unknown whether or not Miedema is looking to leave the Gunners, who she joined in 2017.