He was 5th in the league in OBP and tied Eugene Kingsale, Tjerk Smeets and Evert-Jan 't Hoen for fifth in walks.
[citation needed] He only hit .190/.292/.190 in the Holland Series but Kinheim won the title, breaking the long run by Koolen's old Neptunus mates.
He lost the batting title by six points to Danny Rombley, was second to Fausto Alvarez in slugging and led the league in OBP.
[citation needed] For the 2007 Baseball World Cup, Koolen replaced Yurendell de Caster at second base for the Dutch national team.
[citation needed] Koolen was selected by coach Robert Eenhoorn in the team that represented the Netherlands at the 2008 Summer Olympics in Beijing.