James is on a two season loan at Bayern from Real Madrid.
Rummenigge said: "The cards are on the table: he's with us on loan for two years.
"After that, there is an option which we have the ability to exercise. If I'm not mistaken it's 42 million euros, by no means , although in the current market, we are seeing extortionate prices.
"We'll take things slowly and act when the time comes, which doesn't have to be immediately - or even this year, but we will make a decision eventually."