He was a successful replacement for Jim Leighton but moved on to rivals Rangers in 1996. He made just 20 appearances for the club before he was released in 1999. He played two seasons at MVV before he retired from playing and is a goalkeeping coach in his native Netherlands with FC Twente.
Theo was a part of many Dutch squads but made his only International appearance on 22/03/89 against the USSR. He kept a clean sheet and the Dutch won 2-0 with goals from a Marco van Basten diving header, and Ronald Koeman penalty.
Theo's touch onto the post and then turned behind for a corner from an overly powerful headed pass back from the Dutch defense, resulted in a clean sheet for the Netherlands.