A rugby league player left partly blinded in one eye after a brawl "provoked" the attack, a judge said.
Sean Gleeson had to retire from the game after the incident outside a Wigan nightclub in March 2014.
Liverpool Crown Court heard he was involved in a row with Terrence Riley, 25, who admitted affray, and Lee Jones, 22, who was cleared of the same charge.
Riley received a 12-month community order and was ordered to do 100 hours unpaid work
Recorder Jeremy Lasker said: "In my view the incident was provoked and initiated by Sean Gleeson."
Riley, of Harrison Drive, Haydock, admitted affray and Jones, of Alder Avenue, Ashton-in-Makerfield, denied the offence.
The jury heard Riley become involved in an incident with Mr Gleeson, who was playing for Hull Kingston Rovers at the time after leaving Wigan Warriors, at the Ibiza Club in King Street, Wigan, on 2 March 2014.
Mr Gleeson, who was ejected by the bouncers, got involved in a confrontation with both Riley and Mr Jones outside.
Riley hit the rugby player once or twice and then walked off.
"Two or three seconds later he was struck a heavy blow by Jones. That blow was thrown by him in lawful self-defence," said Mr Lasker.
He said Riley had not gone out that night looking for trouble "but unluckily trouble found you".
The judge added Riley, who has no convictions for violence, was not responsible for Mr Gleeson's injuries or initiating violence.
"You are however guilty of acting in a way that you should not have done having been drinking."
Martin Walsh, defending Riley, said Mr Gleeson had "brought this on himself".
Mr Gleeson, who played for Hull Kingston Rovers, Salford Red Devils, Wigan, Widnes and Wakefield during his career, suffered a fractured cheek bone and has been left partly blind in his right eye. He said the attacks were unprovoked.