"You've seen already he is a player with a lot of energy and someone who can not only score goals but deliver the passes for others. He's much more than just a goalscorer," said Zenden.
"He's shown in one game he's a very good signing for us. I knew as soon as there was interest from England he would be the kind of player who would do well in this country.
"Even before the manager made his decision to sign him, I thought Dirk was a striker suited to this style of football.
"The manager has a lot of choice up front now, which has been his intention all along. He knows you need 21 equal players to challenge."