The Women's Super League has opened an investigation after Crystal Palace used four substitution windows in their 1-0 victory over Everton.
WSL regulations allow teams a maximum of three substitution opportunities during a match. Palace made changes in the 62nd, 83rd, 90th and 97th minutes at the Borough Sports Ground.
The league's investigation will involve Crystal Palace, Everton and Pro Ref, the organisation responsible for referees. Both clubs have been approached for comment.
The rules do not set out an automatic punishment for a breach. However, the matter could be sent to an independent tribunal, which has the authority to issue a warning or fine, impose a points deduction, or apply another sporting sanction.
Lexi Lloyd-Smith scored the decisive goal as promoted Palace began their return to the WSL with victory over Everton.
