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 spent most of his matches during his nine-year tenure at Bundesliga club 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 served as Timo Hildebrand's backup goalkeeper.