EXCLUSIVE

Ex-USC wide receiver Joseph Lewis has been released from jail after serving nearly 6 months of his sentence in his domestic violence case ... TMZ Sports has learned.

As we previously reported, 19-year-old Lewis was arrested back in July after his GF told police he had punched, scratched and strangled her during an argument.

Lewis pled no contest to 1 felony domestic violence charge -- and also admitted guilt in a previous domestic violence incident.

He was sentenced to a year in county jail -- but got out after roughly 6 months due to overcrowding and good behavior.

Now that Lewis is out, he's still not allowed to contact the victim who obtained a 10-year restraining order against him.

Lewis had just 4 catches as a freshman for the Trojans back in 2017 but was expected to be a big contributor this season before he was booted from the team.