Why feel worry? Gündoğan has only one year remaining in City, but if he keeps perform. City can hand him a new contract.
That's why i won't rush to say he's not able to cover a long season with City. I remind you Rodri is back, and having him in the squad will obviously adding the depth to the City's mid.
Gundudgan will get very limited time next season, because, unlike last season, when Manchester City were left with very few options in midfield, Manc City have made some changes. With the inclusion of Reijiers and Cheki, Gunduga won't be a regular player, except more long-term injuries happen.
Rodri is back, and before the new season starts, he will be fully fit, which means he will take back his role as the DM, with Nico as a backup.
Gundugan is not what he used to be. He is no longer that good on the ball and is even worse without the ball. He can't keep up with the intensity, he can't press, and he can't track back regularly. He started declining from his time at Barcelona, he got worse last season and will probably be worse next season. I believe Pep knows that, too, that's why he's so focused on strengthening his midfield.