The Chicago Sky center took to social media Saturday to announce the news ... joking she couldn't imagine her last shot of the season would be a three-pointer -- before saying she's filled with emotion at the premature end to her year.

That said, AR says she's super grateful for whatever comes next ... adding this might be God's timing -- but, at least she can give herself a physical and mental break.

Reese says the league better look out next year ... 'cause they might see her draining more threes.

Reese -- drafted seventh in this year's WNBA draft out of LSU -- averaged 13.6 points and 13.1 rebounds over the course of 34 games.

She set a record with 15 consecutive double-doubles earlier this season as well ... all leading to an All-Star selection and Rookie of the Year consideration.

Of course, Angel's rivalry with Caitlin Clark has captured fan attention this year ... with video of her clapping when Clark was fouled hard by a teammate going viral on social media.

She's publicly denied having a feud with the Rookie of the Year frontrunner in recent months, but fans online are certainly dividing into two camps.