OBS

[Stair-Climber]

I believe that in most cases stradling the base would be obstruction. If stradling the base without the ball gets in the way of the runner rounding the bag, I might give that runner the next base if I felt the runner had a chance to get there. Also, if stradling the base without the ball causes the runner to slow down on the way to that base, I will probably protect that runner to that base.