The 29-year-old was involved in a fight with two men outside a nightclub in Liverpool city centre in the early hours of June 4.
Barton was reportedly on a night out with his girlfriend when the incident took place outside the Garlands nightclub on Eberle Street.
After being arrested, the Merseyside-born midfielder, who lives in Widnes, Cheshire, tweeted: "I got sucker punched in the back of the head.
"Not injured as reported just a small bruise on rear of head/ear.
"I've had worse. Life goes on! Thanks for the concern. Have a good day people."
A picture of the incident, apparently showing a shirtless Barton being held back by police and a woman, was also circulated on Twitter.
A spokesman for Merseyside Police said on Thursday: "Merseyside Police can confirm that four men arrested in connection with an altercation in Eberle Street, Liverpool city centre on June 4 will face no further police action.
"The four - two 21-year-olds from Liverpool, a 29-year-old from Widnes, Cheshire, and a 20-year-old from Liverpool - had been arrested on suspicion of affray, and subsequently released on police bail.
"All four have now been notified by the police that, following advice from the Crown Prosecution Service, they will not face any further action."