The news was confirmed Sunday by Shaq's football team, which released a statement expressing condolences to him and his family. The Bucs write, "Today’s tragic news is heartbreaking for all members of the Buccaneers family."

They adds, "Our thoughts and prayers are with Shaq, Jordanna, and the entire Barrett family during this unimaginably difficult time. While no words can provide true comfort at a time such as this, we offer our support and love as they begin to process this very profound loss of their beloved Arrayah."

The police confirmed it as well -- saying Shaq's daughter, Arrayah, was transported to a hospital Sunday morning after a call came in for a child who'd fallen into the water. Despite life-saving measures, cops say the child was pronounced dead a short time later.

It's unclear what led to the accident -- but cops are saying the circumstances don't appear to be suspicious in nature. An investigation is ongoing ... Shaq hasn't commented.

An even more gut-wrenching detail here is the fact that Arrayah just turned 2 on April 19. Shaq posted an adorable tribute to his kid, writing ... "Happy 2nd bday to my cutie girl. So sweet and cute. You made our family complete. I love you baby girl."

Shaq and his wife, Jordanna, are raising three other children together ... the rest of whom are older at ages 11, 9 and 8.