You have a lot going for you, you've played sports, you have high grades, and you paid your own way thru school. I don't want to diminish your academic accomplishments, but an owner of a company looking at you would probably rank those in order of importance like this - 1)paid his way, 2)played sports, 3)high grades. I guess what I'm saying is don't put too much emphasis on the 4.0. The first time you get hired the difference between 3.0 and 4.0 will unlikely make much difference...it's sad but true. And after you get hired to your first job, no one ever cares what your grades were ever again as long as you live....all they care about is past job performance. That said, if you still want to play ball, college sports is great for relationships and finding a job when you're done. Employers love athletes b/c they understand competition, they understand teamwork and they are passionate about winning.
Debt is also not always a bad thing. It is a great motivator and it can pay great returns. If you have the drive to be successful, the 20K will be a month's pay in a few years...so don't sweat it. If you want to play college hoops and get your degree then by all means do both. Don't sacrifice something you love, you'll second guess yourself the rest of your life. But, if the 4.0 is more important then go for it.