As a qualifier, Theine made it into the main field of the ATP Stuttgart in 1986 , but failed in three sets against the South African Barry Moir . Ultimately, he didn't manage to win a single victory on the ATP Tour , either in singles or doubles. He was more successful on the ATP Challenger Tour , where he won two double titles. He reached his highest ranking in the tennis world rankings in 1989 with position 208 in singles and in 1988 with position 219 in doubles.
In 1988 he qualified for the Australian Open , where he had no chance against Paul Chamberlin . This was also his only single Grand Slam appearance. In doubles, he was twice in the main draw at the Australian Open and once in the Wimbledon Championships .
Theine is the DTB-B trainer and is responsible for the top male players at the KTHC Stadion Rot-Weiss . In addition, Theine has been coach of the Bundesliga team at Bremerhaven TV since 1994.