John O'Shea says Troy Parrott's elevation through the ranks at Spurs could provide a big boost for Mick McCarthy's Republic of Ireland heading into the Euro 2020 play-offs next March.
Parrott became the youngest player to appear in the Premier League this season when he was introduced with five minutes remaining in Tottenham Hotspur's 5-0 demolition of Burnley on Saturday.
The 17-year-old Dubliner, who has scored heavily for the underage sides, made his senior debut in the EFL Cup in September and the Spurs manager hinted that he may feature in Wednesday's Champions League game against Bayern Munich.
Former Republic of Ireland international O'Shea told RTÉ 2fm's Game On that he expects Parrott to get more game-time over Christmas.
"It's huge, it really is. Obviously, there's a lot of hype about him but Mourinho has obviously seen something in training.
"Whether it be his personality, his physicality. You're not going to be able to play in Premier League if you're physically able to cope with it.
"Pochettino had him in training with the first team too. If you're impressing Mourinho and Pochettino, you must be doing something right.
"Fingers crossed, he stays fit and healthy. I'm sure he'll get a bit more game time over the Christmas period and it could be a big boost for Ireland heading into March."
Parrott's apparent progression under the new Spurs manager has surprised many given Mourinho's well known reticence to chance younger players.
For O'Shea, it implies that Parrott must be standing out in training.
"Mourinho will know the scrutiny that he's under. When he's gone into teams, people have said he hasn't really looked at the youth set-up and the younger players coming through.
"When he took the job, he spoke about the academy and the younger and obviously a lot of people would have thought that was a bit of a smokescreen.
"But if a player stands out like hopefully Troy Parrot is doing, it just takes care of itself.
"Harry Kane is going to need that competition and a bit of rest here and there, and if Troy Parrott can get the benefit of that and showcase his talents, it's going to be huge for Ireland."