BBC reports the 30-year-old most recently played for Bath, who released him after he pleaded guilty to an assault charge.
He is the fifth forward among the Warriors' seven close-season signings, but the first since Dean Ryan left to become the Rugby Football Union's head of international player development.
"Everything is in place for you to succeed at Sixways," said Faosiliva.
"Warriors are an ambitious club with a clear vision, which is something that really appealed to me."
