While Michael O'Neill says he would never rule out a player playing for Northern Ireland, he has highlighted the the gap between Leagues One and Two in England.
Paul Smyth is set to make the step up to League One after an impressive season which helped Leyton Orient seal promotion.
Smyth has won three Northern Ireland caps to date, scoring the winning goal on his debut in a 2-1 friendly victory over South Korea in March 2018.
Read next: Prevention work key for PFA NI after Jerry Thompson tragedy woke up Irish League
The former Linfield man hasn't played for his country since 2021 but O'Neill is sure to be keeping tabs on how he does as he steps up next season.
"I think there is a difference between League Two and League One, there is a gap there and the gap is bigger between League One and the Championship.
"Although, what we see in League One is that there are a lot of big clubs, the likes of Ipswich Town, Sheffield Wednesday, Derby County.
"I would never say I'd never pick a League Two but I do feel it's probably a level where the lads have to get out of it.
"Paul is a good example as he's had a good season at Leyton Orient, they've got promoted, so the real challenge for Paul and his club will be seeing how they do in League One.
"That will give us a better look at whether that player is capable of coming in and having an impact at international level.
"League One is a good place for loans; you see that with the likes of Conor Bradley, it's also a good starting point for players coming across and you see that with Eoin Toal at Bolton.
"We have to try and pick players who are playing regularly at as high a level as possible."
O'Neill has been working first-hand with the Under-21 squad in the past week, and he was pleased to get a good look at Patrick Kelly and Callum Marshall, who were both part of West Ham's FA Youth Cup winning squad.
"It's brilliant, PK and Callum Marshall have done really well in camp, they've shown up really well, they're both very young at 18," he said.
"Unfortunately Michael Forbes is injured so couldn't be part of it.
"It's brilliant to see these lads first-hand, the next phase for them is under-21 football at their club sides.
"I saw that Premier League 1 and 2 at Stoke quite a bit, you're coming out at 18 but you're maybe being asked to play against someone that's 21 and there is a gap there in terms of physicality and everything else.
"So that will be a challenge for them, but both players have shown up really, really well here.
"It's always nice to be part of a successful team at that age group, and West Ham have certainly got a very strong academy at this moment."
READ NEXT:
- How to watch this year's Isle of Man TT - TV and live stream info
Tyrone star Kevin Hughes speaks candidly about losing siblings in road accidents
Wayne McCullough highlights 'non-existent' aspect to many emerging boxers
McCullough gives Conlan-Lopez verdict as he outlines 'easy' route to victory
Sign up to our f ree sports newsletter to get the latest headlines to your inbox.
