The Boro defender is a major doubt for Monday night’s clash against Kazakhstan at Windsor Park, with O’Neill revealing the Northern Ireland medics are having to closely monitor the 28-year-old, even though he did play all 90 minutes of Friday night’s frustrating defeat to Denmark.

Injury-hit Northern Ireland were agonisingly close to a big result in Copenhagen when 18-year-old debutant Callum Marshall saw a stoppage-time equaliser ruled out for offside by a VAR check that took a full five minutes.

The defeat left Northern Ireland second from bottom in their Euro 2024 qualifying group, with O’Neill saying that his priority at this stage is nurturing his young squad rather than qualifying for next year’s tournament.

With the likes of Steven Davis, Stuart Dallas, Corry Evans and Shane Ferguson all out of action, McNair, who was already a pivotal figure in the Northern Ireland camp, has become even more crucial, with O’Neill recently talking about the importance of the Boro defender’s leadership skills.

But he might be forced to sit out on Monday.

O’Neill said: “Paddy has just had a bit of an Achilles injury and we’ve had to manage him through this week a little bit.”

Boro will be watching closely, with the start of pre-season fast approaching. McNair endured something of a frustrating start to life under Michael Carrick at the Riverside because of the form of Dael Fry alongside Darragh Lenihan. But Fry’s sending off against Sunderland in January offered McNair a chance, and the former Manchester United man went on to establish himself as a regular.

Meanwhile, the wait for Chuba Akpom to get an international opportunity goes on. He’s in the form of his life and won the Championship’s golden boot and Player of the Year award last season, but the striker was again left out of the Nigeria squad for Sunday night’s African Cup of Nations qualifier against Sierra Leone.

Reports in Nigeria claim the omission was because of the expiration of Akpom’s Nigerian passport, with boss José Peseiro saying: “Akpom is not available for this camp because of some bureaucracy.”

Peseiro has been repeatedly quizzed on the chances of an Akpom call-up on the back of the striker’s blistering Boro form.

In March, he said: “I am a coach, I choose in my mind the best players for our team but if I ask other guys or the 120 million people in Nigeria, they can choose others.

“It’s my job, of course I know this player, I checked this player. You know I visit many players, if I choose this one, at this moment I believe in them more than the others, for that I’m a coach. I have responsibility. For that if I lose, cut my neck, not your neck.

“I appreciate, I know this player. My staff, for each weekend 48 matches at least, watching all the players. Yes, he’s a good player, I agree but at this moment I don’t have enough confidence in him. In the future, of course it’s open for everybody.”

Akpom was born in London and played for England at youth levels through to the Under-21s stage, but the striker has Nigerian parents and in 2019 pledged his international allegiance to the African country, saying: “I’ve been wanting to do that for many years. It was a personal decision. I’m Nigerian and my whole family feel very Nigerian and it will be nice to represent Nigeria.”

Elsewhere, ex-Boro boss Chris Wilder is no longer in line to become Reading manager after talks with the League One club broke down.

Wilder had agreed to take charge but the Royals reportedly changed some terms, including the make-up of backroom staff.