Bayer Leverkusen are Norwich City's biggest rival in the race to sign Celtic defender Kristoffer Ajer, according to the latest speculation.

Newcastle have also been regularly linked with interest in the Norway international but The Athletic report that Norwich and Leverkusen have "overtaken" the Magpies as the "most likely" clubs to sign the centre-back.

As previously reported, the 23-year-old is a player the Canaries are keen on if the financial package works out, with Ajer entering the final 12 months of his contract in Glasgow.

German website Fussball Transfers last week claimed that Bundesliga runners-up RB Leipzig are also monitoring Ajer's situation, in case they can't secure number one defensive target Maxence Lacroix from Wolfsburg, following the big-money sales of central defenders Dayot Upamecano and Ibrahima Konate to Bayern Munich and Liverpool respectively.

The Sun reported last month that a valuation in the region of £10million is likely, as they reported that City would lodge a bid.

AC Milan have shown interest in Ajer previously and he admitted last month while on international duty that "something will probably happen this summer" due to his contract situation, when addressing transfer speculation.

The Athletic report on the Hoops' rebuild after a disappointing season lists Ajer as one of the players who almost certainly won't be at Celtic Park for the 2021-22 campaign.

Leverkusen finished sixth in the Bundesliga so will head into qualification for the Europa League at the beginning of the new season.

Ajer has made 176 appearances for Celtic since joining from Norwegian club IK Start as a teenager, winning three Scottish titles, two Scottish Cups and two Scottish League Cups.

He remained a regular at centre-back during a tumultuous season, as Rangers reclaimed the Scottish crown, but has previously had stints in midfield and at right-back.

VERDICT: Should Leipzig enter the race then it's likely they would be the most attractive option for the Norwegian, both financially and in terms of status, with Champions League football secured.

The tall defender is among the most technically proficient defenders in the Scottish Premiership so could be well-suited to Daniel Farke's possession-based style at Norwich.

His time in Scotland will have prepared him well for the physicality of the Premier League as well and City could use the lure of the world's most high-profile league to offer a potential springboard, as Virgil van Dijk did when he left Celtic for Southampton before stardom with Liverpool and Holland.

Leverkusen would provide very strong competition, clearly, for a team that has just been promoted from the Championship. However, the Canaries are understood to want one significant addition to their central defensive ranks and their spending power has already been strengthened by the sale of Emi Buendia to Aston Villa for an initial £33million.

Fulham's Tosin Adarabioyo and Koln's Sebastiaan Bornauw are also believed to be players that City are monitoring as possible options.

Ben Gibson's loan from Burnley is poised to be confirmed as a permanent switch for around £8million after forming a strong partnership with skipper Grant Hanley before an ankle injury with eight games remaining of City's title success.

Irish 18-year-old Andrew Omobamidele stepped into the breach impressively and is in the mix alongside the more experienced Christoph Zimmermann, who has battled injury issues during the past two seasons.

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