Frankfurt are searching for a new coach after Armin Veh announced he will be leaving the club at the end of the season.
Schaaf has been out of work since stepping down as Bremen coach last May after 14 years in the job.
He is one of the leading candidates to take over at the Eagles and their president Heribert Bruchhagen did not deny he is an option.
"It would be fatal for me to say that Thomas Schaaf is not an issue," he told Sky television.
"That would be degrading towards him. We need a coach who can relate to the situation and economic possibilities we have here.
"Somebody who can analyse the team correctly and who has the right network to strengthen it.
"There are plenty of coaches who fit the bill."