The one-time Burnden Park favourite believes that the Scot has the skills to do the job and was not given enough time by the club's executives.
"Owen was one of the good guys and given time he would have been able to turn things around," he told talkSPORT. "They've got a strong squad but results are everything."
Walker went on to say that Coyle's successor should be somebody with a proven track record of bringing teams up to the top flight of English football.
"Bolton didn't want to take the chance of losing out on the new [Premier League] TV deal that will kick in next season," he added.
"They need a lift and a spark from somewhere. Bolton need someone who has experience of winning in that division and of getting promotion from the Championship to the Premier League."