The S-League has announced that the Courts Young Lions, made up largely of national Under-21 players, fielded ineligible players in their four fixtures so far.
The S-League did not name who they are.
As a consequence, the Young Lions' opponents in those matches have been awarded a 3-0 win.
In a press release, the S-League's director of operations Kok Wai Leong said: "A small group of players who are full-time National Servicemen are further required to obtain written approval from their respective relevant authorities. This was not conducted for some of the affected players in Courts Young Lions."
Aide Iskandar's men had lost to Hougang United (0-1), Tampines Rovers (0-2), Brunei DPMM (1-2) before drawing 1-1 with Balestier Khalsa on Wednesday. Following tonight's announcement, they are back at the foot of the 12-team table with zero points.
Ridzal Saat, the Football Association of Singapore's deputy director of development and planning, said: "We acknowledge the severity of the issue and will be taking internal disciplinary action against officials found to be negligent in their duties."