The grad transfer market in college basketball has exploded in recent years, with players playing 2 or 3 years at one school, graduating, and then being able to transfer without sitting out a year so long as a couple conditions are met.
It’s worked out well for Kansas, who had Tarik Black play 33 games for the 2014 team, and it has worked out well for the players, who get to either prove themselves at a higher level to try and catch the eye of NBA scouts (or try to play in the NCAA tournament), or to drop down a level and get some more playing time with their final year.