When Martin O'Neill dropped a hint at yesterday's press conference that John O'Shea may not start against Serbia tonight, the Sunderland defender will have known that at this stage of his career, player management is crucial.
What he probably wouldn't have expected was his manager jokingly questioning his age.
"Are you 33 this year?" O'Neill intervened as the Waterford native was asked whether he felt like he personally had to seize the opportunity in the upcoming European qualifying campaign.
"In April yeah," O'Shea responded with a wry smile.
"That's him finished! Will someone check what age Richard Keogh is?" came O'Neill's response as the room erupted into laughter.
The reality of O'Shea's situation is that he is one of the Republic of Ireland's most important players and, as O'Neill acknowledged, he knows exactly what he can do on the pitch.
O'Shea understands that he will have to adapt to his changing role as he works to keep up with the demands of both international and club football.
"At international level, like at club level, you soon get to a stage when you realise that it is getting that bit more difficult, but that's natural," he said.
"You can't keep going at the same level of performance later on into your thirties.
"The preparation and your fitness work beforehand and also the extra work that you do like yoga and pilates, it does have an impact.
"If you can maintain it (fitness) and stay injury-free and healthy, it does help."
If O'Shea had his way, though, he'd be one of the first names on the teamsheet tonight – not least because the Sunderland defender wants to rid last Sunday's League Cup final defeat to Manchester City from his system.
Asked whether having a game so soon after was a benefit, he replied: "Without a doubt. Look, we gave it a good shot.
"Unfortunately, Mr (Yaya) Toure came up with the goal that he did, but for the first 50-55 minutes it was going according to plan.
"A second goal would have been nice, but up to the last few minutes we were in with a shot of bringing it to extra-time.
"They scored two fantastic goals, don't get me wrong, but we gave them a good scare. They knew that they were in a cup final, shall we say.
"It is good to have this game, because the sooner the next game comes around, it gets the appetite going again.
"We'll have that at club level after this international game as well.
"It's obviously disappointing losing a cup final. It's as simple as that."
O'Shea, like a lot of the Irish public, is still riding on the high of the introduction of O'Neill as manager and Roy Keane as his assistant, but his sense of realism kicks in again as he acknowledges the tough road that lies ahead.
"You could tell that it had gone really flat. Then the new manager was announced and his decision to bring Roy in alongside him got everyone's imagination and enthusiasm back up," he said.
That enthusiasm O'Shea speaks of is something that he wants carried into the start of the qualifying campaign in September.
And despite the fact that he will have turned 33 by then, his manager is fully aware that O'Shea is central to the Republic of Ireland's hopes of making it to the Euro 2016 finals in France.
O'Neill has signalled his intention to play an attacking brand of football where possible, a contrast to Giovanni Trapattoni's famously conservative approach.
However, he will not adopt a gung-ho approach as he attempts to mould his team and playing style.
He said: "We want to try to score more goals, and the very natural thing is you want to try to create more chances to score more goals, so that's something we would be looking to try to do if it's at all possible.
"We have to earn the right to express ourselves. I think that's really important."