The Belgium striker delivered a superb display and a goal in Sunday's eventual defeat by Newcastle United at St James' Park.
But Roberto Di Matteo confirmed this week a clause exists in Lukaku's loan which allows the Chelsea boss to recall the forward from his loan spell once the transfer window reopens.
And Clarke said: "What happens in January happens in January. That's no concern of mine at this present time.
"Romelu has been a good substitute for us and he has been patient and every now and then you have to give him a chance to play."
Clarke will look forward to next weekend's clash with struggling Southampton in a confident mood despite back-to-back bad luck stories, with a late loss to Manchester City preceding their St James' Park heartache.
He added: "If the players continue to play in the same manner, we will be talking about good points and good victories most weeks, so that is what we have to build on and continue to look at.
"We have to take our frustration into our next game, which is Southampton at home next week. The players know they have played well and deserved to get a minimum of three points at Newcastle, if not three."