England pair Olly Morgan and Mike Tindall and Scotland utility back Chris Paterson all look set to miss the Kingsholm clash after being forced off in Gloucester's 31-7 win within 12 minutes of one another.
"Olly's shoulder is pretty serious, Chris' ribs looked pretty sore and Tins took a bad bang on his shin - in that order. We'll see tomorrow (Sunday)," said Gloucester head coach Ryan.
"Without a doubt, today (Saturday) and next week is going to test our resources. There were some significant injuries out there."
The disruption to the back line took its toll as Gloucester leaked one try and had to defend some intense pressure in the second half at the Stade Pierre Rajon.
But having already secured first-half tries through Anthony Allen and James Simpson-Daniel and an interception score soon after the interval from Ryan Lamb, replacement hooker Andy Titterrell wrapped up the bonus point in the final minute of the game.
"I thought we were outstanding for 50 minutes," Ryan added. "We did everything we talked about, took our opportunities and controlled the game.
"Four injuries down and suddenly that momentum goes. Momentum swings really quickly in France and I thought we did really well just to guts out that last 10-15 minutes with people playing out of position and not quite sure what was going on.
"It's an enormous win. It's the toughest game we had in the pool.
"They were a fired up Bourgoin and I thought our first 20 minutes and then our first 10 minutes after half-time were outstanding and that gave us full control of the game."
The Guinness Premiership leaders now head their Heineken Cup group with 14 points from a possible 15.
But Ryan is far from complacent about their progress to the knockout stages.
"Heineken Cup pool games can swing really quickly," he said. "We've got to look at next week. We'll face a stirred up Bourgoin next week and we'll have some injuries to key personnel in the squad and we've got to get the game out of the way.
"I've not been involved in a Heineken Cup campaign that has not gone down to the last game and we're just looking at the next game."