His talk with the wayward star comes after the big centre half was red-carded for aiming a diving headbutt at a rival player in the pre-season friendly with Derby County at the iPro Stadium on Saturday.
He lashed out after a challenge by Scotland striker Chris Martin and was immediately sent off for violent conduct.
Although the offence carries an automatic two-match ban, he could still be available for the Petrofac Training Cup first-round showdown against Hibs at Ibrox tomorrow.
Referee Mark Heywood’s report is due to arrive at the English FA today.
If they raise the matter with the SFA, Hampden chiefs will take action, but it is understood that, as the process usually takes at least a week, the defender would be in the clear.
However, Mohsni will still be sweating on a potential ban for the SPFL Championship opener against Hearts at Ibrox on Sunday.
McCoist has brought in two new centre-backs – Darren McGregor and Marius Zaliukas – and he will tell Mohsni he must improve his on-field conduct if he wants to be selected ahead of them.
The French-Tunisian netted 12 goals last season, but was also sent off twice.
McCoist fears his suspect temperament could cost Rangers dear against full-time clubs this term.
Speaking after the game in Derby, he said: “Bilel is going to have to learn. There is no excuse for what he did. It has given us a headache we could have done without.
“This is a massive season for us and we can do without stupid suspensions. Bilel knows he let himself and his teammates down. We will assess the situation.”
Zaliukas is set to start tomorrow alongside Lee McCulloch.
McCoist also said he will keep trying to strengthen his squad this month.