Said Marshall, who is not going to be offered a new contract by the City management to the CT: "He can definitely be a Premier League goalkeeper, without a doubt but I personally feel he needs another year in the Championship.
"He has got through this season on how well he has done so far, and deservedly so.
"But he needs another year to know how to get through the good times and bad in football, and I think he needs to learn that at this level.
"That will give him a stronger mentality to deal with the bad times.
"I am not suggesting he hasn't got that mentality, but he has maybe not had enough bad games to test that resolve.
"But the future is bright for him and it is down to Keiren.
"He has got the talent and it is a case of how far he wants to go in the game.
"As long as he keeps doing the right things and listens to the advice he is given, I am sure he will do well.
"I hope I have helped him, and I wish him success