Hamburg midfielder Rafael van der Vaart says on-loan Chelsea defender Jeffrey Bruma needs regular football to fulfil his potential.
Bruma is still tied to Chelsea until 2014.
"We talk a lot with each other. Of course he's disappointed, because he wants to play more often," said ex-Tottenham star Van der Vaart.
"Only he usually makes one or two mistakes. However, I believe that this is mainly to his lack rhythm. If you look at his talent and his physical attributes, he is one of the best."