"The club has never accepted any wrongdoing, but did acknowledge that a technical fault occurred and as such were fined by the Premier League accordingly in December."
Sunderland, which insisted the "matter is now closed," is next-from-bottom in the league, four points from safety with eight games remaining. A points-deduction would have further hurt its hopes of avoiding the drop.
Former Sunderland manager Steve Bruce, who signed Ji in June 2011 and is now in charge at Hull, questioned the apparent leniency of the punishment.
"That's pretty bizarre stuff that it's only surfaced now and he's played in four games," Bruce said. "They should be in serious trouble, I would have thought."
In official FIFA games, if a team is discovered to have fielded an ineligible player a 3-0 loss is awarded by default.
Sunderland's administrative blunder happened after Ji returned ahead of this season from a loan spell with German club Augsburg, which he joined permanently in January.
Manager Gus Poyet, who was not in charge of Sunderland when Ji wrongly played, previously advocated an opponent's points being awarded to his Brighton team when Hartlepool fielded an ineligible player.