Gartside insists he still has faith in Coyle, claiming he will continue to be Wanderers boss "for a long time to come".
The Bolton supremo insists Coyle remains the best man to get the club back up into the Premier League.
"Owen is going to be our manager for a long time to come and he is going to be successful," said Gartside.
"I've known Owen for the best part of 15 years. I know what his qualities are and I've worked with him closely now for two-and-a-half years and I know what his qualities are in the job that he does for the club.
"Owen put a plan together 18 months ago that he wanted to reduce the age of the squad, because he felt there were some older players in the squad that were going to come to the end of what were great careers, and he wanted to put something in place that was sustainable."