"It's a little bit suck it and see, but I daresay he should be right to play in round one," Ratten said on Tuesday.
"Whether we took that almighty risk for him to play with us with the amount of pre-season that he's missed [is what we have to decide].
Ratten said Warnock would be more likely than most talls to be able to recover due to his agility and fitness.
"I know that his fitness levels are enormous because of what he can do in a beep test for a big fella. He can run about a 14.8 so that's up with some of the best midfielders, but we'll just have to see if he has any hiccups and how he proceeds from here.
"He'll be close to round one, [but] whether he plays seniors or Bullants he'll be playing football."
The ruckman who crossed from Fremantle via last year's trade period was on the road to recovery from a shoulder reconstruction when he was diagnosed with the stress fracture that saw him fitted with a moon boot after the Christmas break.
Ratten admitted the boot had stayed on longer than first anticipated, but that reports the 206cm giant would not take the field until midway through the season were pessimistic.
"He's got his boot off, it took about an extra week than we thought, but we'll probably see him back running in a week and a half … From there we'll determine how quickly he gets back to kicking the footy.
"Maybe the thing about midway through the year is for him to get back to full fitness. That might be where the rumour mill got going."
The coach didn't rule out handing the 22-year-old his club debut early in the season and easing him back to peak fitness via the interchange bench.
"It's up to us to manage whether we play him for 40 per cent of game time or something like that. Geez, he'd be handy to come off the bench wouldn't he?" he said.
Ratten’s plans at this stage run to Warnock playing almost exclusively in the ruck and not as a forward target.
"I think when he does play it'll be in the middle whether we take him in as a first ruck or a second ruck.
"That's his position and we need to get him around there. We've got Matthew Kreuzer up [forward] and Cameron Cloke can play there a bit, so how much tall timber can you have there?
"If they're catching it it's fine, but it's instant rebound if they don't. We've got to get that balance right to make sure we're not too top heavy."
