Joey Barton will not face any disciplinary action following his challenge on Dickson Etuhu in Saturday's Tyne-Wear derby.
The Football Association confirmed it was looking into the Newcastle United midfielder's clash with Etuhu in the 1-1 draw at the Stadium of Light.
Barton caught the Sunderland man in the groin with his studs, but escaped any on-pitch punishment from referee Martin Atkinson.
But, on Sunday, the FA said it would investigate the incident once Atkinson's report on the Premier League fixture had been received.
Following a review of the challenge, the FA has now stated that no formal action will be taken against Barton.
An FA spokesman said: "The Football Association can only take action in the case of incidents that are not seen by officials.
"Whilst it is clear that the officials did not see the full extent of the incident, they did see players coming together and to take any further action would be tantamount to re-refereeing the game and this would be contrary to the laws of the game."
If the matter had been pursued, the summer signing from Manchester City could have been hit with a three-game ban for violent conduct.