Martin O'Neill is set to be confirmed as Celtic manager after two interim spells last season, facing what could be the club's biggest rebuild since Ange Postecoglou took charge in 2021. With more than 10 first-team players potentially leaving, including goalkeeper Kasper Schmeichel's retirement and several out-of-contract stars, O'Neill inherits a squad in transition.

The scale of the rebuild is substantial. Celtic have already seen Alex Oxlade-Chamberlain and Kelechi Iheanacho depart while loan players return to parent clubs. Daizen Maeda is likely leaving after his move was blocked last summer, while captain Callum McGregor has expressed concerns about matching his ambition. The club rejected £25m for midfielder Arne Engels in January, suggesting their resolve may be tested again.

Celtic's attacking output has noticeably regressed, dropping from 112 league goals in 2024-25 to just 73 last term. With the Champions League play-off round looming on August 18-19, O'Neill must avoid the mistakes of recent windows when late incomings left the squad unbalanced. The rebuild will require decisive action to restore Celtic's competitive edge domestically and in Europe.