Watford remain interested in signing South Korean defender Kim Min Jae from Beijing Guoan, but Asian Champions League rules could hamper their chances of bringing the player to Vicarage Road in the upcoming January transfer window.

The 22-year-old centre-back, who turns 23 on Friday, joined Guoan last January and has impressed for both club and country throughout the year, earning him the nicknames 'The Monster' and the 'Korean Van Dijk'.

The Watford Observer has been told that the Hornets have retained a dialogue with the Chinese Super League club over a potential move for the player, but that several factors would need to be overcome in order for a transfer to happen.

One of the main stumbling blocks stems from the fact Guoan will be appearing in next season's Asian Champion's League and the competition's specific rules regarding the use of foreign players.

Currently, the ACL rule book states that "Each Participating Club may register four foreign Participating Players, however, at least one of these must have the nationality of an AFC Member Association."

At the moment Kim Min Jae is the only Guoan player who fulfils this requirement, meaning they would have to replace him with another player from an AFC member country.

Should they be unable to do this, it is unlikely they would allow Kim to leave.

Also preventing Watford from putting an agreement in place at this early stage is the fact that Guoan are still in with a chance of claiming the CSL title and are not willing to talk about players either joining or leaving the club until the league has been decided.

However, the CSL culminates on December 1, so there would still be a month in which a deal could be discussed ahead of the transfer window opening.