A few weeks ago the NCAA approved a new rule regarding obstruction. Beginning in 2018, players will be forbidden from blocking or otherwise obstructing a base or home plate until they have the ball. Additionally, the runner can SLIDE and make contact (but cannot run into or "railroad" the catcher) if the defender is blocking the plate. If the defender blocks the plate before possessing the ball, the runner will be called safe.
I think this is a good rule. Major League Baseball created this rule a few years ago after a star catcher, Buster Posey of the San Francisco Giants, was hit by a runner on his way to home plate and suffered a season-ending injury. To better protect its players, the MLB created the rule that to block the plate, you must have the ball.
It makes sense that the NCAA would institute this rule for the same safety reasons.