The pair started in the FA Cup win over QPR.
Alcaraz told evertontv: "He [Stones] is a young lad and he has a big future. He is a great player and I think he is going to improve a lot. He had a great game against Stoke and also now [against QPR].
"He has a lot of quality but he is a young guy and he needs more games to improve and learn. But if he continues in this way then he has a big future and he will make a big impact in the Premier League."