Celtic’s key priority this summer is to improve their defensive line.Ange Postecoglou’s Hoops side have already been linked with a plethora of centre-backs but they now have a fresh target in the pipeline.What’s the word?It’s rare you find Fabrizio Romano dishing out Celtic transfer news but the Italian reporter had a surprising dose on Tuesday evening.Taking to Twitter, he revealed that the club were in the hunt to find a replacement for Kristoffer Ajer.He commented: “Celtic are in direct contact to negotiate personal terms with Swedish centre back Carl Starfelt as potential Ajer replacement. Opening bid set to be made to Rubin Kazan and talks now started.”Another reporter, Anel Avdic, then revealed a potential price tag: “According to our sources at Sport Expressen Celtic is ready to pay around £4m to Rubin Kazan,” he said.Fantastic signingStarfelt might not be in the same mould as Ajer but supporters should be elated if Celtic bring the Sweden international to Paradise this summer.At the age of 26, he’s closely reaching his prime and he’d suit Postecoglou’s style of play perfectly.Ajer is a defender who loves to bring the ball forward, dribbling out of defence on a relentless basis.[snack-amp-story url= “https://www.footballfancast.com/web-stories/read-the-latest-celtic-news-doig-nketiah-mccann” title= “Read the latest Celtic transfer news!”]However, Starfelt is very different to that. Instead, he focuses on distribution, rather than progression. Postecoglou enjoys to play with an intense possession-based system and thus, the centre-back would feel right at home.Last season, he recorded a pass success rate of 91.4%, the highest number of any player in the Russian top-flight.Starfelt doesn’t find himself involved in too many defensive duels, but he very rarely loses out when he does go up against an attacker.The Rubin Kazan brute won 76% of his defensive duels, a higher number than Ajer who prevails in 70%.His tackle percentage is also remarkable, prevailing in a whopping 84%. That means the Swede wins 13% more of his challenges than the man he could replace at Parkhead.A titan in defensive situations, Starfelt is also adept at the modern side of the game, passing out from the back and starting the transition for an attack.At 6 foot 1, he is tall enough to dominate Scottish football and would be a bargain at just £4m.If he and Mario Vuskovic become the defensive partnership next season, fans should be drooling with excitement. They have the potential to end Celtic’s torrid defensive record.AND in other news, Celtic chiefs expect to sign £6.8m gem who’s “like Philipp Lahm”, fans will be buzzing…