Lemina, axed as captain before Pereira's arrival, requested not to be considered for selection for the midweek defeat to Newcastle United.
Pereira said on Friday: "Last time I came to the press conference I thought he was in for the game, then he asked me to be out of the game because mentally he wasn't in condition.
"Today he came to me, in the morning, he asked to apologise to me and apologise to the team. He said he is ready to do his best for the team until we have a solution and decision.
"This is the way he must behave. We are professional, the club pays the salaries which means I should come here with energy to help until the last day."
He also said: "We can commit mistakes in life, I did some mistakes in my life. We must give him the opportunity to show in the act, not with words.
"I believe he spoke with his heart and he will try, I am here to see if he can or not. If he can help OK, if he cannot I prefer to go with another one who is committed.
"Mario has quality, he can bring us physicality in the midfield, technical quality. It depends on his mind. I hope, until the end of the season or the end of the month he will be able to help us."