Ulster surged back into the play-off spots last time out with a comfortable victory over Zebre, but while their top-four fate is in their own hands, they require nine points from their games against the boys in blue and then Ospreys to guarantee their play-off berth.
And with an interpro derby on the line to boot, Williams is battling the clock to get his opportunity to experience the roar at the Kingspan for one final time in an Ulster shirt.
"Kingspan has always been a special place for me," he told the Belfast Telegraph.
"The last game there when the boys played against Connacht was the type you really want to be involved in.
"I've said time and time again this place is my home, almost more than New Zealand. I just want to play my part as much as possible. I've played some of my best rugby here in Northern Ireland and that's because of the boys around me.
"You'd have to ask the medical staff [whether I'll be fit] because it's been slow enough. It's almost a day-by-day sort of process.
"It's part and parcel of the game unfortunately, especially the way I play. It's getting there and hopefully I'll be good to suit up next weekend.
"We're trying to do absolutely everything to get me back on the paddock and it'll be a blessing if I do. Even if I don't, I'll be there behind the boys and giving them all my support."
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