Isaiah Austin's NBA Job Offer -- Work Lined Up ... AFTER He Finishes His Degree

Isaiah Austin -- the projected 1st rounder who's dream to play in the NBA was dashed when he was diagnosed with Marfan Syndrome -- tells TMZ Sports he's got an NBA job lined up ... just as soon as he gets his college degree.

The 20-year-old former college superstar was in D.C. yesterday and told us he's even more motivated to go back to Baylor University in August to finish up his classes ... after a conversation with NBA Commish Adam Silver.

Austin -- who was ceremonially drafted by the NBA at the Draft back in June -- tells us Silver already hooked him up with a part-time gig with the league's NBA Cares program ... and promised full-time work once he gets his degree.

Now, it ain't exactly playing center for the Bulls ... but it's a pretty great deal ... and Austin couldn't be more grateful for the opportunity.