The France international sat out the first game of PSG's title defence just less than a week on from missing its Trophee des Champions triumph over Nantes.
Mbappe's absence was not particularly felt on Sunday (AEST), as a Lionel Messi double and a superb four-goal-involvement performance from Neymar helped PSG to a 5-0 rout of Clermont Foot.
But speaking to Canal+ afterwards, Galtier has assuaged fears the 23-year-old could be a long-term absentee, acknowledging he could have risked him had it been a high-stakes game.
Asked if Mbappe could be back next weekend, Galtier said: "Yes, I think so. He had a little problem, [and] we didn't want to take any risks.
"Obviously, if we had been playing a difficult game or a Champions League game, Kylian might have participated.
"We preferred to delay his return and he will be with us obviously, I think, against Montpellier."
PSG will play its first home game of the season against Montpellier next weekend, with the club hoping to make it three competitive wins on the bounce under its new boss.