CELTIC have identified Matt Mills of Leicester City as the central defender they want to sign this summer.

A bid has been submitted for the player, who was lured to the East Midlands in a deal potentially worth £5m last summer, and Celtic are prepared to offer cash plus Kelvin Wilson.

Mills was signed from Reading by former manager Sven-Goran Eriksson and made captain, but after the Swede was sacked the 6ft 3in 25-year-old fell out of favour under Nigel Pearson and his Leicester career seems over. Wilson had a disappointing season at Celtic after signing from Nottingham Forest and an Achilles injury contributed to him playing only 21 times. He was criticised for the loss of goals in the first Old Firm game of the season and against Kilmarnock in the Scottish Communities League Cup final.

The club allowed another defender to leave yesterday when Daniel Majstorovic joined AIK Stockholm on a two-and-a-half-year contract, and Glenn Loovens is also about to leave at the end of his contract. Celtic withdrew from a deal to bring Jaroslaw Fojut from Slask Wroclaw on a Bosman after the Pole suffered knee ligament damage.

Mills began his career at Southampton before moving to Manchester City and then Doncaster Rovers, where he was a regular before joining Reading in 2009 for a fee believed to have been £2m, and Leicester. His home-town club gave him a four-year contract in a deal which could have risen to £5m depending on appearances. He was given the captaincy, but after a fall-out with Pearson, he dropped out of the team.

Celtic tried various options in defence in the course of the campaign, including Wilson, Majstorovic, Loovens, Thomas Rogne and Charlie Mulgrew, but it has been an area of the side which has still to look settled and trustworthy.

Majstorovic's transfer was announced by AIK yesterday and the move will be completed when his Celtic deal runs out at the end of July.

"It is with great pleasure and pride that I put on my AIK shirt," said the 35-year-old, who made 61 starts for Celtic after joining in 2010 from AEK Athens. "It feels incredibly inspiring to be a part of this exciting project. I have great hopes for the future and look forward to the next two and a half years. Now it's full speed ahead to get fit again."

Defenders Cha Du-Ri, Mark Wilson and Darren O'Dea, midfielder Niall McGinn and reserve goalkeeper Dominic Cervi are all on their way out of Parkhead, too, while another midfielder Ki Sung-Yueng has revealed he will consider his future over the summer.

The South Korean has been linked with moves to Russia and the Barclays Premier League. He has 18 months left of a four-year deal. "Now the season has ended, it's time to relax and recharge my batteries. I will spend the summer looking at my future.

"A story came out last year saying I would be transferred for £10m, but I think it's an exaggeration to talk of those figures. I have said I want to play in Europe and we will see what happens. The important thing for me is to continue my football development at a club where I can play all the time.

"I know my value, or at least how much I think I am worth, but you can't determine the transfer market. There was transfer talk last summer too, but now I am one year older both mentally and physically. I don't know where my future will be and I only want to think about relaxing."