Zeno Debast's real transfer value emerges amid links to Man United and Arsenal

Manchester United are already laying the groundwork for the January transfer window after supporting Ruben Amorim with over £215million. The Reds brought in four players during the summer after enduring their worst season in 51 years.

Benjamin Sesko, Bryan Mbeumo, Matheus Cunha and Senne Lammens were all signed to strengthen Amorim's squad. The window closed last Monday, but there are still glaring issues within the team ahead of the next market opportunity.

Andre Onana's impending departure to Trabzonspor leaves United's number one spot up for grabs. While Lammens' arrival from Royal Antwerp gives Amorim a new option, there are no guarantees he will become the new goalkeeper.

A new midfielder is at the top of the wishlist after interest grew for Carlos Baleba. Crystal Palace's Adam Wharton and Sporting CP's Morten Hjulmand are also expected to be considered when the opportunity next arises.

However, uncertainty over Harry Maguire's long-term future and Lisandro Martinez's unavailability due to injury means another centre-back could be pursued in January, or next summer. Amorim has used Leny Yoro, Matthijs de Ligt and Luke Shaw in his back three with Ayden Heaven and Harry Maguire as back-up.

For the 'next generation', United are expected to look at further bolstering their defence in the future. Fenerbahce's 19-year-old Yusuf Akcicek and Ajax's 18-year-old Aaron Bouwman are two youngsters linked in recent months.

However, Sporting CP's Zeno Debast seems a more logical choice. The 21-year-old was brought to Sporting by Amorim last summer from Anderlecht for a fee of €15.5million (£13.4m) plus €5.5m (£4.7m) in add-ons and made regular appearances before his move to United.

The Belgian international has been linked with a reunion with the Reds boss, with Caught Offside reporting that insiders within the game have suggested he is highly regarded by Old Trafford executives. Arsenal are also thought to be keen on him, having dispatched scouts to observe him in action.

Reports from Portugal suggest that United were considering a €40m (£34.7m) bid in January, significantly below his €80m (£69.3m) release clause. It's believed that Sporting may be willing to negotiate a deal below that amount.

Fortunately for United, the latest figures from the CIES Football Observatory suggest the defender should be valued between €48m (£41.5m) and €56m (£48.5m). Using data from over 8,000 transfers, the website calculates player prices from the five major European leagues using multiple linear regression, with fees paid by clubs as an independent variable.

A move in January, at that price, is unlikely given United's lack of European football revenue. However, next summer could see them leap to the front of the queue for his signature.