The absence of West Ham defender Declan Rice from the Republic of Ireland squad for their UEFA Nations League clash against Wales has set England fans on high alert.
Just 19, Rice is said to have been contacted by representatives of the Football Association (FA) with a view to persuading him to pledge his allegiance to the Three Lions instead of the Boys in Green.
"England have spoken to him," said Ireland boss Martin O'Neill at his squad announcement on Monday. "He is taking time to make his mind up. He has done brilliantly for us. I'm giving him a little bit of time."
So who is the Premier League youngster at the centre of the international tug-of-war? Goal brings you everything you need to know about the Hammers teen, his national team eligibility and more.
Who is Declan Rice?
Rice began his football career at Chelsea, but did not make the grade at Stamford Bridge and was released in 2014, though he did not move far in his next step, joining the ranks of West Ham.
A centre-back who is equally adept at playing in midfield, Rice has enjoyed a swift ascent through the ranks of the east London outfit.
After serving as captain of the Hammers Under-23 team as they earned promotion from the Premier League 2 Division 2 in 2016-17, he was elevated to the first team and was handed his debut by Slaven Bilic in May 2017 as a substitute in a 2-1 win over Burnley.
Bilic kept faith in Rice at the beginning of the 2017-18 season, giving him more competitive minutes from the bench, as well as a full debut in a 3-2 win over Southampton that August.
The arrival of David Moyes as Bilic's successor in November 2017 proved to be a positive development in the career of Rice and he featured heavily for the remainder of the season, primarily in defence alongside more experienced campaigners such as Pablo Zabaleta and Angelo Ogbonna.
In all, Rice made 26 Premier League appearances in 2017-18, starting 15 games, and he also featured in the FA Cup and League Cup. At the end of the season he narrowly missed out on the 'Hammer of the Year' award, coming second to Marko Arnautovic.
Another managerial change in 2018-19 has potential implications for Rice, with new boss Manuel Pellegrini still figuring out his best XI. The signs were positive when the defender was named in the starting XI for the first game of the season against Liverpool, but he was hooked at half-time in the 4-0 loss and was subsequently dropped for the next game.
Rice has indicated that his football idol is former Chelsea and England captain John Terry, a player he has a close personal relationship with.
"When I got released from Chelsea, he gave me a call and we spoke for about 45 minutes. I told him I was going to West Ham," Rice told the Irish Independent.
"He was my idol growing up and to ask him a load of questions and for him to answer them back, I'll always remember that call.
"We live locally to each other and now and then we meet up. We met the other day and we had a catch-up, and he's always going to help me and pass on his experiences."
How does Declan Rice qualify to play for England?
Rice qualifies to play for the England national team by virtue of the fact that he was born in London and is a British national.
An individual's eligibility to play for England rests first upon their having British nationality and then either they, their biological parents or their grandparents must also have been born in England.
However, despite being born in the country and playing for some of its biggest clubs, Rice has never represented the Three Lions at any age level in his career.
He has been touted as a potential future England international though, with West Ham owner David Gold telling talkSPORT at the end of last season that he hoped Pellegrini would help transform the 19-year-old into one.
"I’m looking forward to the new manager turning Declan Rice into a strong England defender for the future of the England team," Gold told the radio station.
Has Declan Rice played for Ireland?
Yes, Rice has played for Ireland at a number of different levels for Ireland, from Under-16 right up to senior level.
The defender is eligible to represent the Boys in Green due to his Irish nationality and the fact that his grandparents were from Cork in the south-west of Ireland.
An Ireland U-17 and U-19 Player of the Year, Rice was earmarked as a future Irish star in the summer of 2016 when he joined O'Neill's squad for their pre-Euro 2016 training camp.
At that time, there was no doubt in the West Ham youngster's mind about where his allegiance lay.
"I'm fully focused on playing for Ireland," he said in an interview with the Irish Independent. "There's no decision to be made. If I didn't want to be playing for Ireland, I wouldn't be here."
Rice later played friendly games against France and the United States, taking his total number of senior caps for the Boys in Green to three, strengthening the belief that his future was with the Emerald Isle in the process.
Gold's aforementioned comments about Rice playing for England caused quite a stir back in May, but they were promptly dismissed by Ireland assistant manager Roy Keane.
"It’s going to be pretty difficult if he’s Irish," Keane told reporters. “And he is Irish. He plays for Ireland. Where else would he want to go?
"If you had a choice: Ireland or England? It’s pretty straightforward, isn’t it? Ireland."
How is Declan Rice able to switch national team?
FIFA's national team eligibility rules and his nationalities (Irish and British) are what allow Rice to make the change of allegiance from Ireland to England, should he so wish.
Players who hold more than one nationality or have acquired a new nationality can change from one national team to another only once, provided they have not yet made a senior competitive international appearance.
Rice has indeed played for the Boys in Green at senior level, but each of those three appearances came in friendly games, rather than competitive matches.
If the defender were to play in Ireland's upcoming UEFA Nations League game against Wales, for example, he would be irrevocably bound to the Boys in Green in the eyes of FIFA. His option of potentially playing for England would thus be eradicated.
Have other players switched from Ireland to England?
A number of players have changed allegiance from Ireland to England, so Rice would not be an outlier by any stretch of the imagination.
Perhaps the highest profile example of recent times is Aston Villa midfielder Jack Grealish, who played for the Boys in Green at various levels before switching to England in 2015. Unlike Rice, however, Grealish never accepted a senior call-up and did not earn a single senior cap.
Another example of a player swapping green for white is Everton defender Michael Keane, who represented Ireland at Under-17 and Under-19 level before declaring for the Three Lions. Interestingly, Keane's brother, Will, could potentially go the other direction after playing for England at Under-21 level.
Will Declan Rice play for England or Ireland?
Right now, it is unclear where exactly Rice stands on the matter, so we do not know how he will proceed.
However, what is certain is that his previously expressed commitment to Ireland, which appeared unshakeable back in March, has been shattered following O'Neill's revelation that he is "still deliberating" on whether or not he sees his future in a green shirt.
Naturally, the news has been received negatively by Irish fans, while former Ireland international Kevin Kilbane - like Rice, born in England - delivered a blunt assessment of the West Ham teenager's equivocation on the matter, commending O'Neill's treatment of it.
Kilbane wrote on Twitter: "I’d rather be ranked 150th in the world and never qualify again than have someone who has played, but needs time to THINK whether they should play for us again. Well done to MON (Martin O'Neill) for transparency."
While former players and fans may be seething, O'Neill has been diplomatic and said that he is hopeful that Rice will eventually make a commitment to the Irish cause.
The ball now very much remains in the player's court and until he makes his intentions known or he appears in either the England or Ireland squad, it will remain a mystery.