Of course, it’s not just appearances, goals and assists that count.
While McGregor, at the age of 33, is in the twilight of his career, his experience and leadership skills would be difficult to replace.
Still only 28, Maeda not only has World Cup experience with Japan but perhaps still has his best days ahead of him – and the same could be said of the even more youthful Engels.
Former Celtic manager Ange Postecoglu waxed lyrical during this summer’s finals about the “world-class” closing down abilities that have made Maeda such a valuable asset, while McGregor has long been the heartbeat of the team, taking on more of that responsibility since replacing Scott Brown as captain in 2021.
All of which makes the both players attractive to potential suitors, as does Engels’ talent and potential for growth.
A possible 2025 move to Wolfsburg for Maeda failed to materialise, while Engels was the subject of interest from Nottingham Forest last term.
Their subsequent drop off in early season form was put down by some to the disappointment of seeing those moves collapse, but both finished it strongly, although not enough to clinch Engels a place in Belgium’s World Cup squad.
Speculation around McGregor’s future is not new, given he has been a top performer at Celtic for 12 years.
He showed his loyalty to the club when giving up his international career to maintain his Celtic form.
However, in April he warned that he was happy to finish his career at Celtic only if they “continue to push and want to be successful”.
That was before their late push under O’Neill snatched the title out of Hearts’ hands, but at his age, McGregor has potentially one big move in him despite, like Engels, being contracted until 2028.
Maeda only has one year left on his contract so, as things stand, Celtic have just two transfer windows to cash in.
