The injury blow also comes just seven weeks out from the Rugby World Cup.
Samoa were narrowly beaten 13-10 by the USA at ANZ stadium in Suva, the second-ever win for the Eagles, led by fly-half AJ MacGinty, over the Manu.
Samoa's coach Steve Jackson said they went in at half-time with a bit of wind in their sails, but overall struggled to execute their game plan at crucial moments.
