The England international joined Sale in 2016 after a successful rugby league career.
Solomona, 28, joined Sale in 2016 and signed a four-year contract two years later that was due to expire at the end of this season.
But after discussions with Sale rugby director Alex Sanderson and chief executive Sid Sutton, the club said that “all parties have agreed to terminate that deal early after Solomona expressed his desire to return to the southern hemisphere”.
Sanderson added: “I would like to thank Denny for his efforts during my time at the club and wish him all the very best for the rest of his career and beyond.”
Solomona moved to England in 2014, playing rugby league for London Broncos and Castleford. He scored 42 tries for Castleford in his first season there.
After switching to union, Solomona made his England debut against Argentina three years later and went on to win five caps – all as a substitute – with his final Test appearance being against South Africa in June 2018.
That means he could switch countries after World Rugby this week approved a significant amendment to eligibility laws, which take effect from January 1.
Players will meet transfer qualification criteria by standing down from Test rugby for three years, and must either be born in the country they wish to represent or have a parent or grandparent born there.
Solomona made one rugby league appearance for Samoa in 2016.