Denmark captain Simon Kjaer has expressed his admiration for international teammate and Chelsea defender Andreas Christensen.Christensen has cemented his position alongside the skipper as part of the back three for Denmark. Tuchel has deployed a similar system at Chelsea because of which Christensen has operated so well at the national level as well.Frank Khalid@FrankKhalidUKAndreas Christensen on Thomas Tuchel. Edit:-@CFCBlogs_12:28 PM · Nov 11, 2021138862Andreas Christensen on Thomas Tuchel. Edit:-@CFCBlogs_ https://t.co/N07POtHju4Kjaer stated that his Danish teammate has the potential to become one of the best central defenders in the world. However, he revealed how Christensen needs to be a little more vocal on the pitch.Here's what he said:"I think he has all the prerequisites to become the world’s best defensive player. He reads the game completely uniquely. He is fantastic on the ball, fast and athletic. He has to shout a little louder from time to time, but it has also gotten better. I think AC is a great defender."The 25-year-old defender has been phenomenal under Thomas Tuchel. It's difficult to think of the last time Chelsea were on the losing end when he played well.Christensen has a calm personality off the pitch and that's perhaps why he goes about his business quietly on the ground for Chelsea as well.He has played alongside some of the finest defenders at Chelsea, including Thiago Silva and Cesar Azpilicueta. Furthermore, sharing the dressing room with Simon Kjaer will definitely have a positive influence on him.Chelsea are yet to extend Andreas Christensen's contract which expires in 2022The Danish defender will be free to leave Stamford Bridge in the summer of 2022 if a deal isn't agreed upon with Chelsea.Cesar Azpilicueta, Antonio Rudiger and Andreas Christensen are yet to extend their contracts. The former's name is pretty synonymous with the success Chelsea has seen in the last few years.Frank Khalid@FrankKhalidUKChelsea were convinced they had finally agreed a new five-year contract with Andreas Christensen only for the defender to demand a last-minute change to the terms, according to reports.3:38 AM · Nov 11, 202120815Chelsea were convinced they had finally agreed a new five-year contract with Andreas Christensen only for the defender to demand a last-minute change to the terms, according to reports. https://t.co/gLNNfoETujRudiger has been linked with a move to Bayern Munich and Real Madrid. However, he has cemented himself as an integral part of the Blues backline, and it is highly unlikely that fans will see him don another outfit next year.Chelsea FC v Malmo FF: Group H - UEFA Champions LeagueHe stated how happy he's at Chelsea, also revealing that he and his agent are currently negotiating with the board for a contract extension.Christensen has been on and off the playing 11 despite barely being on the end of poor performances. However, Chelsea's recent run has given him a lot of confidence and he's looked more comfortable.Fans believe it's only a matter of time before they hear about his contract extension from the club.