The 28-year-old suffered the injury while on Guinness Premiership duty in April and while Ryan insists his rehabilitation remains on schedule, he insists he will not be rushed back into action.
"Mike was never going to play until late September and he's probably still on course to make it then," he said.
"It was only his inclusion in the initial World Cup squads got everybody excited that he might be back before then.
"He won't be a million miles away from the start of the season. We're not pushing him with a timeline as the last thing we want is for him to break down now.
"Each week he does more and we'll see how he reacts to that. At the moment he's still on track for the original timeline."
Ryan, speaking at yesterday's Premiership launch at Twickenham, has also warned new signing Chris Paterson he will have to fight for the number 10 shirt.
Paterson joined Gloucester over the summer and will feature at fly-half for Scotland during the World Cup, but Ryan Lamb and Ludovic Mercier will also be competing for the same jersey.
"Chris Paterson is an exciting player. We've brought him in because he is a dangerous runner and solid goalkicker," said Ryan.
"If he plays well then he will be in the side and that will create pressure on some of the other guys in the squad.
"We're not saying he has come here to play full back or fly-half, he's come here to create pressure on both positions to make sure everybody is playing very well."
Ryan has recruited heavily over the summer with Jeremy Paul, Andy Titterrell, Lesley Vainikolo and Gareth Cooper also among the new arrivals and the Gloucester boss expects his side to be competing for silverware once again.
"The key is to be able to compete at the top of the Guinness Premiership regularly," he said.
"We're moving in that direction and we want to be among the consistently successful sides.
"Leicester lost two finals on the trot but they're challenging every year."