Mandeville was left out of the starting XI for the trip to Gigg Lane following his performance in defeat to Walsall the previous week.
And boss Ferguson said he missed out on a place in the squad entirely because of his reaction to the news.
"His standards were nowhere near last week," Ferguson said.
"I've got to make decisions and I've got to be ruthless at times.
"And his reaction to not playing was not great either.
"I don't think people should accept the situation that they're in one week and out the other.
"He knows himself that last week he was nowhere near the standards I expect from him.
"If I'm going to be a manager that trusts him to deliver performances then mentally he's got to be stronger."
Ferguson confirmed that Mandeville will be back in the starting XI for Tuesday night's Checkatrade Trophy game against Scunthorpe United.
He said: "He'll play. He's definitely going to play.
"Issam [Ben Khemis] will play, [Alfie] Beestin will play.
"The ones that didn't play on Saturday will play on Tuesday night.
"Mathieu Baudry might get another game because he still looks a bit rusty to me. He would admit that himself."