My personal feeling is that he'll be around for at least three years. I especially don't think he'll go after this year for a few reasons:
1)I don't think he's playing as well as Morris was last year. Last year, defenses geared their offenses to stop Morris, but Morris was so good he still got the job done. This year they are geared to stop Hardaway and Burke has benefited from that. Although Burke is a better shooter than Morris, Morris was much better at getting everyone involved in the offense. Morris was simply a great offensive player last year.
2)He's a freshman. You usually don't see them leave unless they are a complete lock for the 1st round. He's far from that.
3)He's five inches shorter than Morris. No matter how well he does in college, that will be a detriment to NBA scouts. I could see him being a decent backup PG in the NBA some day, but his draft stock will always be limited by his height somewhat.
Just my two cents, but I'm not as nervous about him leaving as I was about Morris.