Giroud has struck in both of France's games this week, but Fernandez feels he could be doing much more for the Les Bleus if he was playing consistently at club level.
He explained: "I think he will leave Chelsea this winter, he has to leave.
"If he does not find a new club, it may be complicated. You have to play and have rhythm.
"There will certainly be a discussion with Didier (Deschamps, France coach)."