The dolls on the stand that got both supporters and the media to respond appeared to wear, among other things, t-shirts with the name of a company that sells sex toys.
The club emphasized that it was about mannequins, while in a statement on Instagram it regretted it had happened.
"We have been in contact with them (the supplier) several times to ensure that the dolls are not adult toys," wrote FC Seoul.
The South Korean league announces that it will review whether the dolls violated the league's ban on highlighting obscene material. It will also be investigated whether the incident damaged the league's image and integrity. If a club violates any of these rules, it may result in points deductions or fines.
The South Korean football season started on May 8 behind closed doors after being postponed for more than two months due to the corona pandemic.