Otago coach Phil Mooney said Mirrielees did not commit a crime but the side had team protocols and Mirrielees had stepped outside them.
Mooney confirmed that the incident was related to drinking but reiterated that Mirrielees had not done a criminal act.
"We as a team had set down guidelines at the start of the season and he unfortunately stepped outside them," Mooney said.
"The reality is we have got internal standards that we have to maintain."
Mirrielees had started four of the five games for Otago so far this year and was at the game yesterday, but did not strip.
Mooney said it had still not been decided whether Mirrielees would be available for next week's game against Tasman in Nelson.
He was replaced yesterday by New Zealand colts hooker Liam Coltman who battled away gamely for nearly 80 minutes.
Mooney had high praise for Coltman saying he played through the pain barrier, having come back early from a shoulder injury.
