Devastating news ... Sarah Shulze, a track star for the University of Wisconsin, has died, officials confirmed to TMZ Sports.
She was only 21.
The director for the Dane County Medical Examiner's office in Wisconsin tells us Sarah's death was ruled a suicide.
The Wisconsin Badgers released a statement ... saying, "The Wisconsin Athletics community is heartbroken by the unexpected passing of Sarah Shulze, a junior with the Badger women's track and field and cross country teams."
"Sarah was a beloved daughter, sister, granddaughter, friend, teammate, and Badger student-athlete.