London Welsh have been docked five points by the Rugby Football Union for fielding an ineligible player.
Tyson Keats played 10 games for the Aviva Premiership club, despite not having the correct playing documents.
Last summer, Welsh's then team manager Mike Scott claimed on registration papers that the 31-year-old New Zealander was English following a failed visa application.
The punishment has seen the team move to the bottom of the league table, two points adrift of safety.
Welsh have also been given an additional five-point suspended deduction on top of a £15,000 fine.
They have two weeks to appeal the sanctions.