The Black Cats failed to get international clearance for Ji Dong-Won after he returned from a loan spell in Germany with Ausburg last season.
The South Korean forward reportedly played against Fulham, Crystal Palace and Southampton in the first three matches of the season, as well as the clash with Manchester United in October, without having gained international clearance.
Sunderland alerted the Premier League to the error, and have been fined and will face no further action.
Ji has since completed a permanent move back to Ausburg.
He also featured for the Black Cats in a League cup clash with MK Dons, in a 4-2 win which sparked their run all the way to the final at Wembley.
Ji is perhaps best remembered for his last minute winner against Manchester City on New Years Day during the 2011-12 season.
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