San Francisco police have sought Smith in connection with the incident, but Smith's fiancee -- who told TMZ she was the victim -- said her parents took him to rehab at his request.
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RELATED: San Francisco police searching for Aldon Smith after alleged domestic violence incident
"I wish the best for Aldon. And I'm scared for his life with his addiction. I cannot comment on the altercation, but I can tell you I love him and (am) so happy he turned to my family who considers him family, and hopefully he gets the help he truly needs," Smith's fiancee said.
San Francisco police identified Smith as a suspect in a statement to the San Jose Mercury News. Police said the accuser suffered non-life-threatening injuries.
Smith was last seen proposing to his girlfriend at Gary Danko restaurant just last month. But on Saturday night, there appeared to be trouble between the two and now Smith is wanted for questioning over what exactly happened.
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FULL LIST: Arrests of San Francisco 49ers players since 2012
911 audio says the call came from the fiancée's fifth floor apartment on Bush Street, where Smith was violent with her before he took off through the window.
"The suspect threw her around the room, bit her on the wrist, then climbed out the window," the 911 dispatcher said.
RELATED: Oakland Raiders release Aldon Smith
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Smith was a first-round draft pick by the 49ers seven years ago but was released from the team in 2015 after a string of arrests, the last one involving a hit-and-run.
He then joined the Raiders but was suspended for a year for a substance abuse violation. His trouble continued with a domestic violence investigation in Feb. 2017.
Click here for a look at more stories and videos about Aldon Smith.
ESPN has contributed to this report.