Nathan Wood played 90 minutes on Tuesday as England Under-21s lost 2-1 in a friendly against Croatia on Tuesday
Swansea City head coach Russell Martin says he fears losing Nathan Wood this summer after backing the centre-back to "go to the very top".
Wood, 20, made his England Under-21 debut in a friendly loss against Croatia on Tuesday after a breakthrough season at Swansea.
Wood joined Swansea from Middlesbrough for around £400,000 in June 2022.
"He is a huge asset to the football club, on the pitch and off the pitch," Martin said.
"He's been amazing - a young man who has just grown and grown on the pitch and off the pitch as well.
"He is becoming a real leader in the group. He's an incredible learner and he's incredibly brave with the way that he plays. He will play at the very top, no doubt about it."
Wood, the son of former Crystal Palace and Middlesbrough defender Dean Gordon, came through the ranks at the Riverside Stadium, making his senior debut as a 16-year-old.
But Wood made only two league starts for Boro before joining Swansea in June 2022.
He has since established himself in the Championship, making 35 appearances, and will be part of Martin's side in the south Wales derby at Cardiff City on Saturday.
Swansea sold Flynn Downes to West Ham United for a deal worth around £12m last summer having signed him from Ipswich Town for £1.4m in 2021.
Wood agreed a two-year deal with the option of a further 12 months when he joined Swansea, and Martin is hoping he will last more than one season in Wales.
"He will be a huge asset financially at some point," Martin added.
Swansea City midfielder Joe Allen has recovered from injury and is available to face Cardiff City
"I just hope we get a bit longer to work with him than one season, like Flynn, but we will have to wait and see.
"I look at him and he is 6ft 3in, he is built like a heavyweight boxer and he can run very fast. He displays unbelievable courage and technique on the ball… and just the amount of growth he has had this season - I do fear that [he could leave this summer].
"I don't think it's a bad fear to have. It's one of the reasons we were brought to the club, to develop young players.
"But I would like to be able to keep a few together long enough for us to enjoy some success.
"I know he is doing incredible stuff for us and if he continues doing that until the end of the season, I am sure there will be a lot of admirers."
Swansea will be boosted at Cardiff by the return of Joe Allen, who is set for a first derby appearance in 12 years after recovering from a hamstring injury.
Joel Latibeaudiere and Jay Fulton are back from suspension, while Swansea are assessing Olivier Ntcham's fitness after his stint on international duty with Cameroon.
"I think it will be, without doubt, the strongest bench we've had since we've been at the club," Martin said.