Martin O'Neill has voiced doubts over the futures of Arne Engels, Daizen Maeda and Callum McGregor, and their possible departures would hit Celtic hard.

Engels arrived in the 2024 window from Augsburg. He scored 10 goals in 2024-25, added seven the season before, and recorded eight assists last season, contributing to trophy‑clinching wins over Hearts and Dunfermline.

Maeda peaked in 2024-25 with 33 goals in 51 matches, and added 17 in 2025-26. His 38 assists helped Celtic win ten pieces of silverware, including five league titles.

McGregor, 33, boasts 26 honours, 77 goals and 84 assists. His leadership as captain is vital; a departure would leave a gap in midfield and experience.

Speculation has surrounded all three, but O'Neill is keen to "augment the squad" while keeping the core intact.