Fielder Baserunner interference - right to position

Question
In a slow pitch softball league, I was playing first base.  I felt that the batter would likely hit a weak groundball so I was playing even with first base.  There was a runner on first.  When the ball was popped up toward third base, the runner purposely ran into me.  I had not moved from my position. The runner claimed that I was interfering with his right to the basepath.  The ball was caught, ending the inning, so it didn't really affect the game. To avoid me the runner only would have needed to alter his path by a foot or so, which doesn't seem unreasonable.  In such a situation who has the right to the position on the field?

Answer
Jim,

The baserunner has the right of position. The only way that you cannot be called for interference if you are standing in the basepath is if you are attempting to play a ball that has been hit. Since the ball was at third base you had no right to be in the basepath. Therefore, if he ran you over, there would be no rules being broken by the baserunner.

Jesse