Phil Mickelson Entered Treatment Center for Family Trauma and Addiction

Phil Mickelson voluntarily checked himself into an addiction treatment center amid ongoing personal issues ... TMZ Sports has learned.

A rep for Phil tells TMZ Sports ... "Phil was seeking treatment for family trauma and addiction."

We're told the pro golfer sought the treatment recently, and he's already out of the facility.

Phil's reps previously said in June, "Mr. Mickelson's priority is to become the husband, father, and man his family deserves. Right now, that means giving his full attention to a private family health matter. He understands that parts of his life are public, but his family's private matters are not."

Phil has also been open about his longtime struggle with gambling addiction ... saying in 2023 that he had crossed the line from moderation into addiction and had sought professional help for years. He said the habit had taken a toll on his personal life.

As we've reported ... Phil made headlines a few months ago after several accusations of sexual misconduct surfaced -- beginning when Golf Digest reported he made "nonconsensual and inappropriate physical contact" with a female employee at a San Diego golf course.

Shortly after Golf Digest reported the incident, Ashley Perez -- golfer Pat Perez's ex-wife -- alleged Phil showed her a picture of his erect penis back in 2015, then propositioned her while she was still married to the other golf pro.

At the time, Phil fired back at the author of the article, calling it a "drive-by shooting."