Celtic have told interested clubs the price they will have to pay to sign centre-back Kristoffer Ajer, Football Insider reports.

What's the latest transfer news involving Kristoffer Ajer?

The report discloses that the Hoops are looking to receive a fee of £15m for the Norwegian, whose contract expires at the end of next season. 

What teams are interested in signing Ajer?

The report suggests that Norwich are set to make an offer for Ajer, after having earlier bids turned down.

Sky Sports disclosed last month that German side Bayer Leverkusen were in talks with the Hoops about signing Ajer, with The Athletic reporting that both Leverkusen and Norwich had £10m bids for the player rejected.

The Daily Record reported earlier this week that the Canaries were set to make a £12m bid.

How does the fee compare to Celtic's previous player sales?

If Celtic do get the £15m the club reportedly want for Ajer, then they will be earning more money than they did for selling two players who went to the Premier League, Victor Wanyama and Virgil van DIjk.

As Transfermarkt shows, the Bhoys received £13.05m for Wanyama from Southampton when he moved to England, and £14.13m for Van Dijk.

Ajer would be the third highest transfer fee Celtic have ever received should the Hoops get the £15m, with only Kieran Tierney's £24.3m move to Arsenal and Moussa Dembele's £19.8m move to Lyon generating more cash for the Glasgow side.  

Perhaps then it would be a good idea for the Hoops to put a sell-on clause in any deal for Ajer. That is what the Bhoys did when van Dijk moved to Southampton, and the Daily Record reported that Celtic picked up £6m from his subsequent transfer to Liverpool.

If Ajer goes on to be a hit in the Premier League, then he could perhaps follow in van Dijk's footsteps and earn a move to one of the biggest clubs in the division.

Should Celtic hold onto Ajer for the Champions League qualifiers?

One aspect that Celtic will have to keep in mind when possibly selling Ajer is timing. In less than two weeks, the Hoops take on Midtjylland in the second round of the Champions League qualifiers.

A win in that tie would keep the club's Champions League hopes alive, and it would also provide a good start to the Celtic career of recently appointed manager Ange Postecoglou.

The Bhoys will have a much better chance of beating the Danes if Ajer is in the side, so perhaps it would be smart to try and delay any departure until after the tie is over.