I don't see this as losing, it was a beneficial agreement for both teams. Although Ilkay Gundogan was the captain of the team, I don't think he was the key name of the team, he had an important role, but there are other alternatives to play his role. We will see a different central midfield game in City this season. Chelsea are really falling apart one by one, how will the team be re-formed, big losses were experienced last season, they say goodbye to their good games this season. I have no doubt that he will adapt to City Kovacic, communicate with his teammates in a good flow.
Kovacic is good, but not nearly as good as Gundugan.
Gundugan was a little bit underrated in that Manchester City team. He was a key part of that squad. The team can survive without Kevin De Bruyne but I don't think they could survive with Gundugan. They had nobody that could play the role Gundugan had. Now that they have Kovacic signed by City he can play that role. Like I said Kovacic is not as good as Gundugan but Pep knows what he's doing. He's going to turn him into the kind of player he wants.
When De Bruyne was absent, Gundugan stepped in for De Bruyne, but De Bruyne cannot play the CM midfield role like Gundugan. That was how important he was to City.
I'm not worried because Pep will find a way to make things work and I know Gundugan will fit very well into Barca and continue to be a top player.