The flanker has been facing a race against the clock to return for Wales in time for their tilt at the record books as the defending Six Nations champions.
Never before have a country won the tournament three times in a row and Warburton is itching to be fit for the Italy clash that opens their 2014 campaign.
But Gatland, head coach of the Lions this summer, thinks it may come a week too soon for the openside.
"Probably he won't be available for the Italian game," said Gatland.
"We'll just see how next week pans out."
Warburton, meanwhile, is hoping to do enough in the intervening ten days to give his head coach a selection headache.
"I think I'll be available for selection. I need to have a chat with [coach] Warren Gatland and the medics early next week to decide what's the best thing to do," Warburton said.
"We have a chance to win three Six Nations in a row and create history."