The Netherlands international, 29, explained that a minor injury was the reason behind his demotion and rejected claims that he was annoyed with coach Pep Guardiola for not introducing him before the 71st minute.
"Of course I would have liked to have come on earlier," Robben told TZ. "But that's normal.
"But I also had slight muscular discomfort during the final training session. That was also the reason why the coach put me on the bench."
Toni Kroos put Bayern ahead against Leverkusen but the home side equalized almost immediately through Sidney Sam.
In spite of the draw, the Bavarians still moved a point ahead of Borussia Dortmund at the top of the Bundesliga standings.