The Norwegian teen had a loan move to Rennes blocked by FIFA regulation last summer and will spend the coming months with Castilla.
Kroos feels Odegaard's development remains on course.
"We've trained together several times. This is a very young player, so it's not easy to enjoy many minutes in a club like Real Madrid.
"From my own experience I know that it is very good to train with the first team at just 17 or 18 years of age," reasoned Kroos.