Chelsea and contract renewals of it's players are a strange chemistry. Something many don't understand. Well, I guess that's how Russians handle business. There are multiple players who are on their last year of contract but we are yet to see any advancement.
Christensen and Rudigar both were on the transfer list before Tuchel came and won the Champions League. In the four man back line, Frank Lampard preferred young James more than Azpilicueta. In midfield, Declan Rice was still Lampard's transfer wish, and Jorginho would be offloaded in that scenario.
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The reason was, of course. Rudigar was not the leader Rudiger then who we know today. He struggled in a back four, Christensen was the same. Azpilicueta doesn't have the pace to track back anymore, his ability to give accurate crosses has decreased. Basically, the process of reorganizing Chelsea would have started if Lampard had been there then. Lampard's plan was to bring a fresh leg, create a backline that felt comfortable in the back four, and bring Rice to fill the spot with a leader and physical midfielder that could play a single pivot. Lampard could have changed the situation in time, or at least that's what many of us believe.
The new coach Tuchel did not oust them like Lampard but shifted most of them to a system which will give better output. I am talking about Tukhel's 3 man back line and a double pivot in midfield. As a result, many of the flaws have been covered, and many have become world class. Playing right center back in back 3 does not issue with Azpilicueta's pace, because he has Reece James is in front of him. Thiago Silva is already a legend, nothing bothers him.
Rudiger was shaky in the back four system but he has reinvented himself in the left center back position in the back 3. His confidence has reached the peak. Now he will do well even if he plays in the back four.
Christensen is physically Weak, the two year Bundesliga loan ruined him well. He had no confidence, no leadership quality. But Rudiger suddenly becoming a leader in the back 3 and in the regular game with experienced Silva and Azpilicueta, he did not have to worry too much about leadership in the new system.
Not even fan favorite Kante in midfield is flawless. He's an Interception specialist but most of the time he's out of position and can't track back in all situations because of his age. He picked up a lot of cards in Lampard's system, but before that when he was paired up with Matic, he was something out of this world. Tuchel recreated Kante's favorite double pivot at Chelsea, this time his partner Regista Jorginho. Jorginho himself shielded the defense by sitting back in Zone 5, and in turn gave Kante a license to take a forward run. Due to this, Kante got back his 2016/17 identity. On the contrary, Jorginho had no pace, physicality, no tracking back, so under Lampard he would often faced consequences for it, and made reckless tackles and pick up cards regularly. And in the wingback position, young Reece James and Ben Chillwell have adapted themselves to their qualifications. They were back four players, Still they have improved himself for the team.
Ultimately Chelsea have learned to play as a team under Tuchel and have had success in winning the Champions League but looking back a little, these players were supposed to be out of the team long ago. Despite the hopes of a successful season, Chelsea will have to start sorting out the team again without them, an overhaul in the deeper side of the field is long overdue. Perhaps the Russians have seen it before us? Maybe that's because they are not renewing because they're planning on something bigger? Who knows.