Improving a squad which may yet finish the season with all of Scotland’s major trophies is no easy task for Ange Postecoglou.

But the Celtic manager has forged a reputation for attacking the signing market with the same intensity he demands of his players. With another summer of transfer fun and games just around the corner, work will already be well under way at Lennoxtown for what’s to come.

There will almost certainly be a departure or two, and not just among Celtic’s fringe players, but the club have been remarkably pro-active in plugging squad gaps and building further on areas of strength. A return to the Champions League next season will colour this summer’s business, with Postecoglou determined to implement a levelling up process that will allow Celtic to make good on his ultimate aim of being highly competitive on the continent.

With that in mind, what areas will he be looking to make changes?

GOALKEEPER

With Joe Hart now into his 37th year, the search for a long-term successor is likely to begin sooner rather than later. The extension of Scott Bain’s contract solidifies his position as back-up and is further useful in keeping Celtic on the right side of UEFA’s homegrown player quota, but is not reflective of Postecoglou’s intentions for the number one jersey.

The absence of Benjamin Siegrist from recent match day squads suggests he could be off come the summer, and while it’s been said Tobi Oluwayemi is being lined up to move into the role eventually, his 20th birthday was only a fortnight ago and it may be a little too early for him yet.

READ MORE: Ian Maxwell says referee had doorstep defecated on after VAR hysteria

That raises the possibility of a new goalkeeper arriving this summer. Hart has been an excellent signing, bringing leadership and experience as well as reliability between the posts over the last two seasons. But it has long been noted that the former England international is not the most proficient with the ball at his feet, and this is a real difference-maker in the Champions League.

Hart comes from perhaps the last generation of keepers for whom this was never really an absolute requirement. It won’t be the end for him at Celtic, but he may not be an automatic first pick come next term.

DEFENCE

It’s hardly a shocking revelation, but the importance of Cameron Carter-Vickers to Celtic’s backline has been underlined since his season was ended by a knee injury. The USA international has been a colossus, so it’s little wonder there’s been a considerable void since he dropped out.

If Postecoglou’s much-changed line-up in the 3-0 defeat to Rangers was intended as a learning exercise, he may just have concluded that Yuki Kobayashi isn’t quite ready for regular action. He may yet be one day, and deserves time to develop, but Celtic may need to consider a more oven-ready alternative to Carter-Vickers for next season.

Stephen Welsh appears to be well out of the picture now, and for the sake of his career should consider other options if opportunities are not going to be forthcoming. Elsewhere, with two options apiece at right-back and left-back, re-enforcements in those areas do not feel as likely. How Alistair Johnston fares will be one of the more intriguing elements of next season’s Champions League campaign.

MIDFIELD

Postecoglou’s options are perhaps stronger in the middle of the pitch than anywhere else, with no fewer than six players who have all featured to some degree over the last month. Whether any major business is conducted here likely depends on a first-choice player leaving.

Reo Hatate and Matt O’Riley are, you feel, bound to attract interest over the coming months. Should they stay, there is little doubt they will remain in Postecoglou’s preferred midfield trio alongside Callum McGregor. The Celtic manager, however, has made a habit of getting ahead of the game in areas where richer clubs may come calling.

READ MORE: The Celtic record on the line as champions could surpass Lisbon Lions

Add in the distinct possibility David Turnbull will leave before the start of next season, plus Aaron Mooy’s advancing years, and suddenly a new number eight doesn’t seem out of the question. There may yet be a role for B team prospect Ben Summers moving forward, but despite being in and around the first team regularly of late, his actual involvement on the pitch has been very limited.

In Iwata, Postecoglou seemingly has an able deputy for those very rare occasions where McGregor isn’t available to play, or where the manager sees fit to give his captain a breather.

ATTACK

Another area where Postecoglou is loaded with options, but similarly that may change as the summer progresses. He has long prepared the Celtic support for the eventuality that some of their heroes may exit stage left before they’re ready to bid them farewell, but with the emphasis being that this is all part of a strategy to keep the club moving forward.

Liel Abada has been the most strongly linked with a departure, albeit the Israeli winger seemingly dismissed such speculation in a recent media appearance. He hasn’t figured quite as prominently in Postecoglou’s plans this season – injury played a part, of course – but he remains a high potential footballer on whom Celtic could make a satisfying profit.

READ MORE: Referee and VAR named for Celtic vs Inverness Scottish Cup final

If his stock is not going to rise any further in Glasgow, now could be the optimum time to cash in. Jota is an obvious jewel in the crown in terms of potential transfer fees, but the Portuguese star is not quite the finished article as yet, and barring an irrefusable offer his development is still surely best served by staying at Celtic; he is another for whom a further crack at the Champions League will be highly appealing.

Kyogo’s goalscoring exploits will no doubt have turned some heads, but Celtic will have placed a high valuation on their talisman, who seems to relish life in Glasgow more than any other of Postecoglou’s imports. The signing of Oh-Hyeon Gyu in January makes a move for another striker less likely, with additions on the flanks potentially higher on the priority list.