The Ibrox manager has already signed several players this summer, but is still eager to recruit another defender.
McCoist told RangersTV: "I'm delighted with the signings we have made. We would still like to strengthen, especially in the centre-back area, that would be ideal.
"When you look back to last season, we were very light up front at times. We have brought in big Jon [Daly] and Nicky [Clark], who are proven centre-forwards and hopefully will prove to be good goalscorers for us too.
"I would still like to add another body in that area but these two will certainly strengthen the striking department."
Rangers will spend next season in Scotland's Second Division, having been crowned Third Division champions last campaign.