The former health minister won the leadership last March.
One option for Couillard might be the Montreal riding of Viau if incumbent Emmanuel Dubourg decides to jump to federal politics.
There are reports Dubourg may run in a byelection to be held to replace Denis Coderre, who is seeking to become mayor of Montreal.
Couillard told a news conference on Wednesday that one possibility would be to run in the Saguenay-Lac-Saint-Jean area where he lives.
It is unclear whether he will run in a byelection or wait until the next general election, which is expected next spring.