He said: "It doesn't always happen that way with players and I'm sure if Shaun signs, he will relish the chance to return.
"We are always looking to improve and he is another good player.
"We have a good squad as it is now and we know Shaun can play in a number of positions.
"He had a good spell at Celtic the first time, so I'm sure he will do well again."
Hartley, who missed Scotland's draw against Northern Ireland last night with an ankle knock, is confident Maloney's return to Parkhead will also rejuvenate his international career, benefiting both club and country.
He said: "We have five or six Scottish internationals in the Celtic team already, so he will be another good addition.
"I played with Shaun at international level and I know what he can bring to the team."