David De Gea was one of the highest-paid goalkeepers in Europe. But his performance has reduced drastically in recent times, yet he still wants the same wage. Manchester United is unwilling to grant him such a lucrative contract. Andree Onana will be a better and cheaper alternative. He is still young and will spend more time with the Red Devils. If the deal to bring Onana fails the club might consider bringing back the loaned Dean Henderson from Nottingham Forest and also put much effort to sign the Japanese international goalkeeper Zion Suzuki.
De Gea's performance is not too bad He is even included in the ranks of the 4 best goalkeepers in the Premier League based on the number of goals conceded after all the success of Manchester United finished in 3rd place was due to De Gea's efforts it's just that Manchester thinks his ability will slowly decrease and they need to regenerate. I agree if the salary should be lowered and allocated to a new goalkeeper unfortunately De Gea did not agree and had to be released.
De GEA is now 32 with having nearly 12 years here at Old Trafford done impressive job but in last season he lost faith of new coach Erik ten and just because of this management not agreed with him even he was cutting his salary because mostly were feeling now it's time for the change, so they release him and now heading for the new goalkeeper with most chances Onana could be arrived but if this not happened then most chances Henderson could be first choice goalkeeper for the start of this season, and then we can expect new entry into winter transfer window.
Even right now they are having few good options, but they will be not done anything in hurry because they need to have the best available option with in their budget which will give them long term service as well.