Gordon Hayward 'Will Be Fine' After Horrific Injury, Says His Dad

Don't worry too much about Gordon Hayward ... 'cause God's got his back -- so says his family.

"Thanks to everyone for all the messages, prayers & love," Hayward's dad tweeted late Tuesday night ... after his NBA superstar son snapped his ankle in his 1st game with the Celtics.

"We know that Gordon will be fine & God has big plans for him! #Godisgoodallthetime," he added.

Hayward's wife, Robyn, also believes he's in good hands ... posting this on Wednesday morning:

FYI, Gordon hurt himself trying to catch an alley-oop against the Cavs in Cleveland. The official diagnosis was a fractured left ankle ... putting the rest of his season in jeopardy.

Warning: The following video is extremely graphic.