Alan Shearer believes that John Stones is showing few signs of improvement at Manchester City.
Stones joined City from Everton for £47.5million in the summer, but has endured a difficult start to life at the Etihad Stadium.
The 22-year-old was awful as City slipped to a 4-0 defeat to the Toffees at Goodison Park on his first return to his former club on Sunday.
Speaking on BBC’s Match of the Day 2, Shearer questioned whether the centre-half actually is the real deal.
“John Stones did have a nightmare,” he said. “My concern with him – and I don’t want to criticise him but he is 22 now – is that he has played nearly 100 Premier League games and everyone keeps saying to me and to the rest of the football world, that he is going to be a top player.
“But I keep seeing John Stones make mistake after mistake after mistake.
“I don’t know what’s happening with him at Man City but I don’t think he has improved as much as people would think he has this season.
“If I’m a centre forward, a young guy and I keep on missing chances, I don’t expect to be in the team. Eventually you are going to get left out. I keep seeing Stones making mistakes too often, too many times.”