The 21-year-old Fa'alogo is set for at least four weeks in the No.1 role due to an ankle fracture to Ryan Papenhuyzen, starting with the home clash against fellow competition leaders Cronulla on Saturday night.
Slater, now Queensland coach, keeps giving back to the club where he played 319 NRL games and won multiple NRL titles.
"Billy comes in one day a week and works with our outside backs and our attack coach Marc Brentnall," Melbourne's general manager of football Frank Ponissi told AAP.
"He has been enormous to the development of our players and especially our outside backs.Â
"Sua has been knocking on the door now for nearly 18 months. He has done a lot of work on his game, and a lot of work with Billy Slater and Paps."
Fa'alogo, signed at the Storm until the end of 2028, has played two NRL games and scored three tries that showcased dancing feet, instinct and electric speed. Those attributes are rare, but it is another key quality that Ponissi regards as key.
"He has a thirst to get better and improve areas of his game he needs to," Ponissi said.
"Being patient is not a great quality with a lot of players these days. They want it now, but he has bided his time and now a great opportunity arises for him and he gets to play his first home game in a Melbourne Storm jumper at NRL level."
The Storm have been adept at winning close games this year because they compete on every play, a trademark Slater trait.
His involvement - despite Maroons, business and media commitments - is never taken for granted.
"We feel very fortunate to have someone of Bill's talent," Ponissi said.
"He genuinely cares about this football club. Of all his qualities and talents, that to me is the highest. Bill wants to continue the legacy."
The Storm are down on troops in the spine with Papenhuyzen and half Jahrome Hughes (calf) on the injured list and playmaker Jonah Pezet out for the year with a ruptured ACL.
"Paps had surgery (Tuesday) and it all went to plan so he is on track (to miss) that four to six week period. There were no complications," Ponissi said.
"Jahrome has a slight strain so he will miss two weeks and then we are hoping to have him for the Manly game in round 12.
"We have got the bye after Manly so it will be a matter of whether we get him up for Manly or after the bye. We will decide that in the next two weeks."
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