Adrien Silva is recalling when he was banned from playing after a Premier League club tried to sign him, only this episode has nothing to do with Leicester City and the deadline-day saga that ended with an international footballer running round a field to keep fit between talking to lawyers. Silva is rowing back to 2005 instead, when he was 15 and José Mourinho tried to talk him into joining Chelsea along with two other young Sporting Lisbon players.

“It was a very strange moment and I was so young,” Silva says. “To have this club approach me, especially when Mourinho comes to talk to you … at this time, we didn’t know why he came. But when the club wants something, they do everything. He came to see me in Portugal and we went there, to Chelsea, to see the training ground. Then we came back and it was a big, big situation with Sporting.”

Mourinho came to see me in Portugal and I went to Chelsea, to see the training ground. It was a big, big situation Adrien Silva

Sporting were furious and, as well as making a complaint to Fifa about Chelsea, refused to allow Silva to train and play for them for two months. The other teenagers, Fábio Ferreira and Ricardo Fernandes, joined Chelsea and were both released four years later without playing a game. Silva, however, spoke to his parents and chose a different path, harbouring concerns that Chelsea “wanted to win now and not wait for young players”. That he went on to make 241 appearances for Sporting and become a Portugal international suggests he made the right call. “Thanks to God,” says Silva, smiling.

It is a timely story on the eve of Sunday’s FA Cup quarter-final against Chelsea but all the more so in the context of what happened last year, when Silva faced another enforced absence, after Fifa rejected Leicester’s application to register the midfielder because his £22m move from Sporting had missed the transfer deadline by 14 seconds. Barred from playing until January and initially prevented from training with the Premier League club, Silva spent six weeks living with his agent at the Marriott hotel in Leicester, where they exhausted every avenue, including taking his case to the court of arbitration for sport, to try to overturn a ruling that left him angry and upset.

“I had some injuries in my career but then you know why you don’t play and that’s part of football, so you can accept it,” Silva says. “But this situation wasn’t correct. It wasn’t correct because I was able to play physically and I didn’t do anything wrong to make this situation. I will never understand the decision of Fifa – even after Leicester had tried everything to change it. There is no protection for the players in this situation. The players are the most important, so why don’t [Fifa] think about that and make some exception? OK, if it is so many hours [after the deadline], but we’re talking about seconds here. So I think it was a very poor decision.”

This is Silva’s first national newspaper interview since joining Leicester and one of the things that comes across during an enjoyable hour in his company is that he was just as confused as everyone else when the window closed. Told that the media did not know for a while whether he was a Leicester or a Sporting player, Silva shakes his head, grins and replies: “Me neither.”

Sporting, however, appeared keen to provide some clarity. Within days Bruno de Carvalho, Sporting’s president, said: “The transfer of Adrien is already completed. Hopefully Leicester find a solution for him.” Those comments gave the impression that Sporting were washing their hands of any potential problems and, with that in mind, it is interesting to know whether Silva felt any frustration with how his former club acted. “Not with Sporting. With the president. And that’s different,” Silva says. “He tried, I think, to protect his club. But in football it’s more important when you represent a club to protect the human or the player.”

Facebook Twitter Pinterest Adrien Silva poked fun at a frustrating situation by choosing No 14 as his squad number at his new club. Photograph: Plumb Images/Leicester City FC via Getty Imag

For all his annoyance with Fifa Silva admits to fearing the worst as soon as the window closed. “But after Leicester and my lawyers told me that we could make an appeal, I got my hopes up and I tried to keep my head right,” he explains. “I trained alone at the gym and on a field to try to keep my physical condition because I wasn’t allowed to train with the team.”

Establishing exactly why he found himself in this position is not easy, other than to say that negotiations were extremely complicated, with Silva making many concessions to Sporting in order to get the deal done. Leicester were committed to completing the transfer come what may and always maintained that the paperwork was uploaded on time, yet Fifa argued otherwise and refused to allow Silva to fast-track his appeal through Cas. So who, ultimately, is responsible? “We still don’t know,” Silva replies. “For me, I think Fifa the most. But I’m not worried about it now.”

There was one thought that troubled him more than any other as the fiasco rumbled on. Silva loves representing his country and was part of the Portugal team that defeated France to win Euro 2016. Suddenly he could see a World Cup on the horizon and his place in the squad in jeopardy. “Every day that was on my mind,” he says. “And that makes it worse. When I think about it, it was the worst moment for this to happen.”

In the end Silva decided he needed to have a joke at his own expense, to keep his spirits up if nothing else. When Leicester asked what shirt number he wanted, it was the perfect opportunity. “I was talking with my agent, Pedro, who was here with me for a month and a half at the hotel, supporting me every day – my wife and children couldn’t come because I didn’t have a home – and I said: ‘We have to play with this situation. Why not No 14?’”

Quick guide Silva's limbo Show Hide How Portugal midfielder’s move to England unfolded 31 Aug 2017 On deadline day, Leicester open talks with Sporting Lisbon, and announce a deal in the early hours, “subject to clearance”.

5 Sep Fifa reveal City missed the deadline by 14 seconds. Sporting tell Fifa to “show some common sense”, and urge City to pay the money. 4 Oct Leicester’s appeal is rejected, leaving Silva in limbo. 1 Jan The move is finally sanctioned by Fifa – and Silva makes his full debut at Fleetwood in the FA Cup.

The long-awaited debut, wearing that number, arrived on 1 January – Craig Shakespeare, the manager who signed him, had departed two months earlier – and Silva was given a rapturous reception as he came off the bench. “So many things were going through my mind,” he says. “But the main thought was: just play football. It’s my passion and it’s such a simple thing to do. But that day I felt like I wanted to eat the field!”

Silva breaks into laughter after making that last remark and it feels good to see him in a much happier place. On the pitch, he admits, he is still striving to get to his best but life is coming together in other respects. Margarida, his wife, gave birth to a baby girl last Sunday and four days later Silva celebrated his 29th birthday with a recall to the Portugal squad.

Margarida, Silva says, was a huge support to him throughout her pregnancy – he smiles as he checks that the word “hormonal” is correct in English – and he wants to express his gratitude to the rest of his family as well as a couple of players. “Matty James and Andy King – they helped me in every way. They kept pushing me when some days I was down. So they have been very good friends during those months.”

Sporting thanked Silva for his services by inviting him back to the stadium in October for a special tribute to a player who joined them at the age of 12, when he moved 400km away from his family in a country where he was still learning the language after growing up in France. “All those years came into my mind so it was very emotional,” says Silva, who was in tears on the pitch. “Sporting made me into a player but they also made me into a man, and they will always have a special place in my heart.”

It has obviously been a tough time for Silva and it is hardly surprising to hear him say that the deadline-day mix-up was the worst moment of his career. Yet he also sounds full of positivity as he looks to the future and pictures a perfect finale to the season. “I hope we can get past Chelsea and reach the FA Cup final,” Silva says, smiling. “And to go to the World Cup after, that would be the best way for it to end for me.”