After the initial draft you will have three freshman, three sophomores, three juniors and three seniors. For your freshman, you choose any four consecutive seasons. For example, if the have LeBron James on your team it might look something like this:
freshman LBJ 2010-11
sophomore LBJ 2011-12
junior LBJ 2012-2013
senior LBJ 2013-2014
After he “graduates” he goes back into the draft and someone else will get a chance to use him. They can then choose whichever four consecutive seasons they want to use.
The same players and seasons will be used over and over again, but I don’t think it will be overkill. For example, the 1966-67 Wilt Chamberlain will play in the league only once every four seasons.
In other progressive leagues if someone gets LeBron James they can either play him for 20 seasons or trade him for other assets. In this league he (and every other elite player) will be up for grabs every four seasons.