Jordan Spieth -- Calls Out Dirk Nowitzki ... Let's Foursome!

He's already got a green jacket ... now Jordan Spieth is looking to make another dream come true -- dude wants to golf with Dirk Nowitzki.

Turns out the 21-year-old is from Dallas and happens to be a big fan of the big fella -- and when we asked if he could golf with any celeb in the world, the first name that came to mind was Dirk.

Good news for Jordan ... the feeling's mutual -- in fact, the Dallas Mavericks star fired off a congratulatory tweet at Spieth right after he won the Masters this weekend. So, it seems pretty likely they'll end up on the links together.