The young Northern Irishman has significant business to attend to on two fronts.
One is inextricably linked to the other, you would venture, and thoughts of the beach are some way off.
McCullough’s dual aim is to play his part in helping Doncaster Rovers to somehow retain their League One status in the final three weeks of the season and also secure a place in Northern Ireland’s squad for the Euro 2016 finals in France.
He could not have any more to play for.
The 22-year-old centre-back is the first to admit that events so far this season have been thoroughly bitter-sweet.
On the one hand, the Portadown-born player has been as proud as the next man at being involved with Michael O’Neill’s band of footballing brothers, who booked Northern Ireland’s place at their first major tournament for 30 years.
Tthen there is the day job, with McCullough part of a Rovers side who have plunged into freefall during a horrendous run of form of nightmarish proportions this calendar year.
Eight points adrift of safety with five games to go, Rovers face the not inconsequential matter of a visit from League One leaders Wigan Athletic today.
It is fair to say Rovers are massive underdogs, though given his previous experiences with Northern Ireland, that is certainly nothing new to McCullough.
He was forced to take relegation on the chin in his first full season as something approaching a regular at Rovers in 2013-14 and he faces a distasteful encore if things do not change fast.
“This season has been bitter-sweet, I suppose you could say,” he says.
“Like Northern Ireland, we are the underdogs here in our situation and the mentality is similar.
“There’s massively a lot to play for, for me and to have a chance of going there (to Euro 2016), I will have to keep putting in performances here, which is the priority obviously.
“I am not sure if I might be picked in the squad and have had to push it to the back of my mind really when I have come back here where my focus has had to be.
“But I am definitely hopeful of being in the finals squad and have been in near enough every squad in the qualifying so there’s no reason why not, but we will have to see what happens.”
McCullough, capped five times by his country, has suffered along with his Rovers team-mates during a desperate run which has seen them go 16 matches without victory since January 2.
The fact that he has added another string to his bow as an auxiliary defensive midfielder has been negated by his disappointment at overall team results.
His frustration was compounded during a grim Easter when Rovers lost back-to-back games against Colchester United and Blackpool and he was away on international business and was an unused substitute in Northern Ireland’s friendlies against Wales and Slovenia.
McCullough, whose last international appearance came as a late substitute in the famous 3-1 qualifying win over Greece at Windsor Park on October 8 which booked his country’s place in France, added: “It was an awkward situation. I went to international duty expecting to play at some point in both games really and it ended up not happening.
“That was taken out of my hands and I tried to come back here and carry on where I left off with performances. It was just one of those things.”
Thoughts of France are on the back-burner as Rovers strive to end their epic and unwanted sequence this afternoon and while the odds are firmly against them in achieving their safety mission, McCullough is not giving up hope yet. He added: “It is a horrendous run, everyone knows that.
“But we have just been trying to do the right things in training every day and come in and work hard, hoping and believing we are going to put it right eventually.
“There’s only five games left, but we are just hoping the run will change.
“It is most definitely difficult and a bit of a shock to everyone and no-one expected it to happen and it’s happened all of a sudden. But you have to keep going through the hard times and good times.
“We are definitely hurting, if you aren’t in the position we are in, then there’s something wrong.
“But we still do believe going into games we can win them and deserved more in our last few games, but just weren’t able to do that.”