Heinen played most of his matches in his nine-year stint at Bundesliga side Bayer Leverkusen, before moving to Eintracht Frankfurt. In 2002, he transferred to Süper Lig side Denizlispor, but returned to the Bundesliga after just one season there, this time joining VfB Stuttgart. There, Heinen was the substitute keeper for Timo Hildebrand.
Heinen played most of his matches during his nine-year career at Bayer Leverkusen, before moving to Eintracht Frankfurt. He then transferred to Denizlispor in the Süper Lig, but returned to the Bundesliga and became the backup keeper for Timo Hildebrand at VfB Stuttgart.