Soliola, who has missed just one of Saints' 19 Super League and cup matches so far this year, sustained the injury playing for the Exiles in last Friday's 30-10 defeat by England.
"It is disappointing to lose Sia, who has had to have an operation," Saints coach Nathan Brown said.
"The upside is that it gives another player the chance to step up and stake a claim for a place.
"Our squad as a whole has gained vital experience throughout the course of the year and I have no doubt we will adapt and continue to develop."
Brown has called young forward Joe Greenwood into his squad for Friday's game at Salford while experienced prop Anthony Laffranchi returns after a two-week injury lay-off.
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