Martin O'Neill and co are still working the phones ahead of Tuesday's transfer deadline, with midfield reinforcements among his priorities after Celtic's Champions League exit at the hands of LASK.

The Hoops fell from 4-0 up on aggregate to crash out of Europe's elite competition in Austria, with Benjamin Nygren's careless backpass sparking the collapse and skipper Callum McGregor admitting his side had "got away with it" a week earlier in Glasgow. It was a chastening reminder of just how exposed Celtic can be through the middle, and it's put extra urgency on landing a genuine defensive midfielder before the window shuts.

Yves Bissouma has emerged as a serious option in that department. The former Tottenham man is still a free agent following his exit from Spurs at the end of last season, and reports suggest Celtic are plotting a move, with no transfer fee required and no urgency dictated by the window given his contract status.

Bissouma has faced questions over his discipline in the past, but his quality has never been in doubt, and former Hoops boss Ange Postecoglou labelled him "outstanding" during their time working together in north London. Signing him would give O'Neill a genuine upgrade in defensive midfield - he is a Europa League winner after all - without breaking the bank.

But Celtic are also eyeing a versatile alternative in Niko Sigur, and Football Insider's Pete O'Rourke has provided a significant update on that front.

Celtic target says tearful goodbye with deal now close

"I think that's a deal that they could potentially get over the line," O'Rourke revealed on Saturday, with Hajduk Split now willing to cash in having wanted to keep the player to help their UEFA Conference League qualifying campaign, which has now been successful.

"He's been a long-term target for Celtic throughout the summer. They even looked at him in the last January window. Sigur is a player who won't cost a massive amount as well.

Sigur's Hajduk manager, Gonzalez Garcia, also spoke about the midfielder's imminent departure following Thursday's dramatic 3-2 win over Rakow Czestochowa which sent the Croatian side into the Conference League league phase.

He said: "We cried together in the dressing room with Niko Sigur. I think this is the best way for someone to leave. He was very emotional, along with Rokas Pukstas, because they are both probably leaving. Niko gave an inspirational talk to his teammates before the start of extra time too. I'm proud of how he and Rokas fought for the team."

Sigur, who only turns 22 in September, is exactly the sort of player Celtic could use right now, providing international quality at the base of midfield while also providing depth at right-back and centre-back, such is his versatility. He made 29 league appearances for Hajduk during the 2025/26 campaign, producing one goal and three assists, also representing Canada at the 2026 FIFA World Cup.

Wolverhampton Wanderers are also understood to be interested, but Football FanCast sources understand the Hoops will press ahead now Split's stance has softened, with a fee of around £3.5m expected to be agreed in the coming days - the player himself is keen on a move to Glasgow, too.

Elsewhere, Celtic are also weighing up a move for FC Utrecht's Adrian Blake, with the winger seen as a potential upgrade on the underwhelming Sebastian Tounekti. Valued at around £2.5m, the 21-year-old has already impressed against Celtic in the past, scoring a stunning consolation goal at Parkhead last season, and has started this campaign strongly with two goals in his first three Eredivisie appearances. Reports suggest Blake is 'keen to join', and with Tounekti failing to justify his place, this looks a deal worth pursuing before Tuesday's deadline.