Morrison has signed a two-year contract with the Tanzanian league winners after recently parting ways with Simba.
The former Bucs midfielder was initially put on special leave by the Dar es Salaam outfit before cutting ties last week.
Yanga SC official Hersi Ally Said confirmed that Morrison is now their property.
"He is our boy, you know that. He is back", Said tells Kickoff.com from Tanzania.
"He has signed a two-year contract", he added.
Yanga SC is also the new home to former Kaizer Chiefs striker, Lazarous Kambole after he signed with the club recently.