The young winger is currently in the second year of a two-year loan spell. The initial fee for the two years was €7 million, but Bayern have the option to make this deal permanent at the end of the 2016-17 season should they want to keep Coman.
Rummennigge confirmed that this was highly likely.
"There is a huge probability that we will exercise our option to buy Kingsley," he told 'TZ'.
Coman played a total of 35 times for Bayern last season, scoring on six occasions. The 20-year-old also has 11 caps for France.