Dislodged base

[greymule]

Yesterday, in a modified-pitch game, PU made the following call at 3B. I was BU, and with another runner going into 2B, this was PU's call. However, when the throw went to 3B, I ran over anyway and got a good look.

As a runner slid safely into 3B, he managed to jab the toe of his right shoe into the center of the top of the base. With his slide, his foot dragged the base (not spiked down) a little more than a base width, so that it lay in foul territory a few inches from the line. The runner kept his foot nailed to the middle of the base and did not try to advance in any way. No part of his body was where the base had been originally. F5 tagged the runner, and PU called him out.

Naturally, the offense screamed, but PU ruled that the runner had in fact overslid the base—that his foot was not where the base had properly been.

I'd have called that safe, since he kept his foot on the base and didn't try to advance. I think that had it not been a movable base, he would not have overslid. But a reading of the ASA book makes me wonder about that play. What if the runner and his slide had carried the base five feet across the foul line? What if the base had been spiked down and the runner's foot had simply spun it into foul territory, still attached to the spike? What if the slide had kicked the base five feet foul, and the runner had gone over and stood on it, making no attempt to advance?

Finally, what does the ASA book mean in 8-9-N by "The runner is not out . . . when the runner slides into a base and dislodges it from its proper position. The base is considered to have followed the runner."