2:27 PM PT -- Tributes for Bill are pouring in from all over the world -- and, former President Barack Obama even posted in his honor -- remembering Bill as a grinder on the court and for his wonderful spirit off it.

Bill Walton -- the NBA legend who delighted fans for decades both on the court and in the commentary booth -- has died, according to the NBA.

The league put out a press release Monday morning announcing the sad news ... saying Bill passed away after a prolonged battle with cancer. He was surrounded by family when he passed.

NBA Commissioner Adam Silver remembers Bill as a dominant force on the court and a colorful personality off it ... while also lauding Bill for his positive, upbeat personality at league events.

Walton played college basketball at UCLA from 1971 to 1974 before the Portland Trailblazers drafted him with the first overall pick in the '74 draft.

Bill played four seasons of his career in Portland where he won his first of two NBA titles and an NBA MVP award before moving on to the Clippers and the Celtics. Injuries forced him to miss significant time and changed the trajectory of his playing career.

Younger fans will know Walton better from his broadcasting career ... he started commentating with ESPN on NBA games in the early 2000s before transitioning to college basketball in 2012 where he remained for the rest of his life.

Bill's survived by his wife, Lori, and his four sons -- Adam, Nathan, Chris and Luke ... the latter of whom followed his father's footsteps into the NBA first as a player and later as a coach.

Bill always had time to talk about his passion and his friends ... including with us back in 2016 when he gushed over superstar singer John Mayer.

Bill was 71.

RIP