John Stones broke all sorts of transfer fee records when he joined Manchester City in 2016 to help them retain the domestic glory.
And while City did retain their glory, Stones didn’t play a big part in it.
Now, a couple of years later, Pep wonders where it went wrong.
“He has the conditions to do it, but to be the best central defender you have to play one entire season, every three days being there,” Pep said, quoting Sky Sports.
“It’s difficult to reach the potential that he has, he has to be at the level to play regularly. The last three seasons and a half he could not do it.
“Sometimes when you have a tough injury – for example like Aymeric [Laporte] had this season or [Ilkay] Gundogan in the first, or [Benjamin] Mendy the year he arrived – it’s unlucky.
“But in the case of John, I don’t know why he has not been able to play regularly.
“We try to help him. We have tried to do the best to help him since the first day of the three-and-a-half years we have been here. We do everything for him.
“It depends on him. It’s in his hands and in his head to become one of the best.”
While Guardiola still clearly believes in Stones, things have to change quickly for the English defender.