The Chelsea midfielder says his time away from the club was ideal for his progress.
He told the Daily Mail: "My development at every age group was good. If I was playing in one age group, I always wanted to play the year above. And then it came to the stage where I was in the [Under-] 23s and I needed that extra push.' He went to Vitesse Arnhem for a year and then to Derby, under Frank Lampard.
"I went to Holland and had a good season where I learned a lot about a different type of football. And then going to the Championship. We all know what that's like, how tough it is.
"And that added a different part to my game. And then back to Chelsea and giving it a really good go. And it just happened."