The Charlotte Hornets star rookie -- the #3 overall pick in this year's NBA Draft -- suffered the injury Saturday night while trying to make a spectacular shot against the L.A. Clippers at Staples Center.

Ball landed on his right wrist -- and appeared to be in pain immediately.

Ball clutched his wrist before getting it checked out by a team doc -- and now, ESPN's Adrian Wojnarowski says the injury will almost certainly end Melo's sensational rookie campaign.

The Hornets announced an MRI confirmed Melo has a fracture in his right wrist. No official word on how long he'll be out.

But, Woj -- citing sources -- says it's just a matter of time before he's formally shelved for the season.

Woj notes the injury specifically affects "the area of the thumb on his shooting hand" ... and Ball will be following up with Dr. Michelle G. Carlson at the Hospital for Special Surgery in NY to confirm he needs to undergo a procedure.

Melo has been killing it this season -- averaging 15.9 points per game -- along with 6.1 assists and 5.9 rebounds.

He was the frontrunner to win the NBA's Rookie of the Year Award ... we'll see if the voters feel he's done enough in his shortened season to give it to him despite the injury. Seems like a lock at this point.