College Track Star Shelby Daniele Reportedly Died Of Brain Aneurysm

Shelby Daniele -- the college track and field star who died suddenly at 23 years old last month -- passed away from a brain aneurysm ... her close friend's dad said.

Brian Brandenburg -- whose daughter, Eva, committed to Cal Poly this year in large part because of Shelby -- revealed the sad news in an emotional post on his Facebook page.

"The young lady that was the driving force in Eva's decision to run Track at Cal Poly, Shelby Daniele, passed away last night of a brain aneurism (sic)," he wrote. "Completely heartbreaking."

"This is Eva's 3rd day of classes and practice," he added. "Hug your children every time you can and tell them you love them every day. Please say a prayer for Shelby and her family."

The school announced Shelby's death over the weekend, praising her for her skills on the track ... while calling her a "one of a kind" person who "will be missed dearly by everyone in the Cal Poly community." School officials did not at the time, however, release a cause of death.

Daniele -- a captain on Cal Poly's squad -- won All-Big West honors six times. She also held a school record in the indoor 200-meter race.

She had just received a degree from the university in June -- and had vowed on her LinkedIn page to try to "improve the environment and give back to our society" in the future.