Something must be done to stem the tide of young, undeveloped players leaving college for the NBA after just one year. This trend hurts the NBA by filling team rosters with players who aren’t ready to be pros, but it’s also a problem for college basketball.

There are no great teams in the college game. Elite players don’t stay on campus long enough to develop the kind of cohesion with teammates that produces greatness. Now, when you see a special talent like Jared Sullinger, the 6-foot-9 freshman from Ohio State, you know he’ll turn pro after the season. Great talents leave early because the NBA is where the money is. College rosters are filled with the very good players left behind.

Back in the day, college players couldn’t join the NBA before their senior class graduated unless they could prove economic hardship. That’s how Isiah Thomas left after his sophomore year to join the Detroit Pistons in 1981. Eventually, proving financial hardship was deemed unnecessary and players like Kobe Bryant and LeBron James jumped from high school to the NBA. The talent pool in college basketball has been shrinking ever since, and too many teenagers have failed to follow in the footsteps of James and Bryant.

In 2005, NBA commissioner David Stern established 19 as the minimum age for NBA players. His intentions were good, but too many players now treat college basketball as a one-year showcase for the NBA. Those freshmen drop out of school during the spring semester to prepare for the NBA draft—even though some of them won’t get drafted.

Here’s a solution: The NBA should mandate that every college player stay in school until age 20. The NBA can’t touch him until then. As for the ballers (and their attorneys) who would argue this is unfair to 18- and 19-year-olds, give them the option of playing in the NBA developmental league until age 20. Odds are those players would prefer college. There’s a benefit to spending time on a college campus. Having NBA hopefuls stay in college until age 20 will help them whether they become pros or not.

Clearly, the current system needs fixing. When an NBA team drafts a player after just one year in college, it doesn’t know if it’s getting a John Wall, the former University of Kentucky star who has excelled with the Washington Wizards, or a DeMarcus Cousins, Wall’s college teammate, who has struggled on the court and off. Last week, the Sacramento Kings disciplined Cousins for fighting with a teammate.

The NBA should raise the league’s minimum age to 20 to increase the odds of sending more mature men to the pros and improve the quality of college basketball.

Cecil Harris is the author of three books, including Charging the Net: A History of Blacks in Tennis from Althea Gibson and Arthur Ashe to the Williams Sisters.

Image:  Andrew Bynum, the youngest player to ever play in an NBA game.  Jeff Gross/Getty Images