Mason, 22, acquired a two-year prison sentence, suspended for 2 decades, for assaulting a woman in 2018.
An estimate at Sheffield Crown Court also placed Mason on the sex offenders’ register for seven decades.
A Doncaster statement read:”Rovers have cancelled the contract of Niall Mason afterwards he retreated an appeal against his dismissal by the club”
It lasted:”Rovers opened inner workings immediately after his guilty plea for a sexual offence at Sheffield Crown Court.”
Defender Mason have been a routine for its promotion-chasing League One side until shortly before his court appearance in January, but had been suspended after his probation.