Johnston started the last two Scottish Premiership games after impressing in his second-half performance against St. Johnstone earlier this month.
However, the winger was poor in Celtic’s 2-1 loss at Kilmarnock and was taken off after 70 minutes the Bhoys crashed to a shock defeat at Rugby Park on Sunday.
The Ireland international has been a bit part player at Celtic this season and McGinn indicated that he is likely to become a fringe option once injuries clear up for the Bhoys.
He stressed that this was Johnston’s chance to prove that he has a future at Celtic but conceded that the player completely allowed it to pass him by without making an impact.
McGinn said on the Go Radio Football Show: “Brendan Rodgers couldn’t have [done] other than just coming out and saying, ‘Listen, Mikey, Daizen Maeda and Liel Abada are nearly back, we are about to strengthen the forward areas in January and you had the last chance at Celtic and this is the very last chance. We are going to Kilmarnock and you will be playing, do not miss this opportunity’.
“And I feel he missed the opportunity.
“I thought Ndaba dominated him physically and he was better than Mikey Johnston in attacking as well.
“Mikey Johnston would not have believed the chance that came around at Celtic but I just feel he hasn’t taken the opportunity.”
It remains to be seen whether Johnston starts when Celtic take on Feyenoord in the Champions League on Wednesday night.
