"As long as there's no infection or anything like that we're pretty hopeful.
"It just depends, maybe the end of next week at some point and hopefully he'll track pretty quickly after that."
In Luke's absence, rookie pair Jazz Tevaga and Nathaniel Roache filled in admirably against the Titans, and will again share the dummyhalf duties for Saturday's home clash against South Sydney.
Tevaga will again start the match and his strong tackling will be needed against a powerful Rabbitohs starting pack containing Sam and Tom Burgess, and John Sutton, with Roache set to make an impact throughout the second quarter.
Luke's injury has also deprived the Warriors of a goal kicking sharp-shooter, but McFadden confirmed halfback Shaun Johnson is set to reclaim the tee duties this weekend after managing a quad injury over the last two months.
Against the Titans, fullback Tui Lolohea managed only two from four attempts and missed one from close range following Solomone Kata's first try.
Johnson took the final shot at goal after Kata's second four-pointer but was unsuccessful having enjoyed very little practice since first straining his leg in the round 14 win over Newcastle.
"He'll probably start to do some more goal kicking, you'll probably see Shaun take over that role this week," said McFadden.
"He hasn't a lot of practice. A bit of that has been helped by the fact that Issac was kicking so well.
"So it was a blow to lose him last week and we lost him late as well."