Aside from ‘is he any good?’ and ‘can we afford him?’, there’s nothing a manager wants to know more about a player.

So, there’s a fair chance Yang Hyun-Jun has answered a key question for Brendan Rodgers before even meeting him: how desperately does he want to play for us?

In the South Korean winger’s case, quite desperately indeed.

Since news of Celtic’s interest broke back in June, the 21-year-old has become embroiled in a very public dispute with his club, Gangwon FC, as he attempts to engineer a move to the Premiership champions. Such situations tend to get messy rather quickly, and this has been no exception.

There have been claims and counter claims emerging from Korea over the past few weeks, from Yang himself, his representatives and from Gangwon. The latest was the winger publicly declaring on Sunday after his side’s K-League defeat to Incheon that he was willing to forego his own salary in order to help strike a deal.

It was a quite extraordinary step for a player to take, as he pleaded: “If the transfer fee isn’t enough, I’ll even give my own salary.”

Considering how rapidly and publicly this dispute has escalated, you’d be right in thinking the seeds for it were surely sewn some time ago. According to the player’s representatives, Gangwon rejected an approach for him from MLS club Minnesota United last year. Given he is under contract until 2025, it's claimed the club then promised they would not stand in Yang’s way if an approach was to come from Europe this summer.

READ MORE: Yang Hyun-Jun in incredible Celtic claim as he offers to pay transfer

However, in the intervening time, CEO Lee Young-pyo has been replaced by Kim Bjung-ji, who appears to be taking the stance that promises made on someone else’s watch are no longer binding. The club’s reasoning is that letting one of their top players depart midseason – the K-League campaign does not conclude until October – would be highly detrimental to Gangwon’s push to avoid relegation from the top-flight.

They currently sit second bottom (11th) of the division after 20 matches, six points behind Suwon FC above them and only three ahead of Suwon Bluewings below. The K-League is structured very similarly to the Premiership; a 12 team setup which splits into a top and bottom six after 33 games, one side is automatically relegated, while the team which finishes 11th contests plays the K-League 2 side which progresses through the promotion play-offs.

Gangwon have won only two of their 20 games so far, and you would not currently fancy their chances of pulling away from the bottom. The club changed manager on June 15, replacing toiling Choi Yong-soo with Yoon Jong-hwan.

There’s been no new manager bounce, however, with Yoon losing two of his first three matches in charge. The club’s plight has no doubt complicated the situation, and it is probably no surprise that CEO Kim is digging his heels in instead of sanctioning a transfer which would make him wildly unpopular with Gangwon fans. It is also not an ideal way to aid a recently-appointed manager tasked with avoiding relegation.

Only in the job a fortnight, Yoon – while refusing to directly intervene - has already suggested he is unhappy with how the situation is playing out.

"It's a club and agent problem, not something I'm involved in,” he said. “I hope to work quietly so that it will not be revealed. We keep making the situation difficult by disclosing it to the media."

Celtic are believed to have made an official approach for the player last month, which has only heightened Yang’s resolve to get his way. His comments, and that of his representatives, have been about as strong as you’ll see, outright accusing Gangwon of breaking promises.

“He is hurt,” a statement said. “The club have gone back on their word. The offer from Celtic is in the same bracket as what they paid for Oh Hyeon-gyu and is more than Gangwon's combined profits over the past ten years. And it also had a sell-on clause. Yang is extremely grateful to everyone at Gangwon. They are the club that made him, and he understands their predicament. However, he wants to play in Europe."

READ MORE: Celtic look certain to abandon South Korea pre-season plans

The decision now for Gangwon is whether they now allow this to keep dragging on or decide to cut ties with Yang and take the money. They would likely bank a club-record fee from the deal, but it is not money which can be used to address their current, alarming predicament.

With Jota set to leave Parkhead for Saudi Pro League champions Al-Ittihad for a fee in excess of £20million, Celtic are expected to step up their efforts to make Yang theirs. With no shortage of transfer cash at Rodgers’ disposal they could be tempted to up their offer further, but are unlikely to pay over the odds now for a player they know will be much easier to sign in just a few months’ time.

Marco Tilio has been added to Rodgers’ attacking options already, and with Daizen Maeda, Liel Abada, Sead Haksabanovic, James Forrest and the returning Mikey Johnston still on the books, Rodgers won’t be facing an emergency over wide options any time soon. Celtic will have backup options ready to be actioned upon but having gone all-out to bring Rodgers back they will want to secure as many of his first-choice targets as possible.

Keeping an unhappy player, important as he may be, does not often work out well for already-struggling clubs, especially one who feels opportunities to move have already passed him by. Celtic fans, meanwhile, will feel encouraged by a player so desperate to pull on the green and white jersey, even if the lengths he has gone to in making that clear could be considered a touch extreme.

Either way, the club’s interest in Yang is confirmation of Rodgers’ assertion that they would continue to tap into the Asian market, which has been so fruitful over the last two seasons. It is likely that witnessing what Celtic has done for his countryman Oh Hyeun-Gyu and the strong contingent from neighbouring Japan has strengthened Yang’s resolve.

He is in no mood to delay his European dream any longer, but whether he succeeds this summer remains to be seen.