does a fielders foot count as part of a base?

Question
Hello, we had a softball game where a runner over ran 3rd and when attempting to get back to the base slid in and was kept from touching the base by the 3rd baseman's foot. The runners foot was on top of the fielders and did not touch the base until after the tag was applied. The umpire in this case called the runner safe. Is the runner entitled to get back to the bag unblocked or is he out? Does it make any difference that he was trying to get back to the bag as opposed to just getting there? What about blocking the base on any other occasion. I've been called out before when being blocked at home and second. Is it OK to block the base in ASA?  Thank you, Ron

Answer
Hi Ron,

In any situation a defensive player cannot block the base unless they have possession of the ball.  If F5 had possession, their foot can block the base and make their tag for an out, otherwise no.  If they did not have possession it is obstruction and the runner is protected and would in this case be awarded 3rd.

Since the runner was called safe I "ASSUME" the runner slid, hit F5's foot and THEN F5 received the throw and applied a tag.  This would be obstruction.

Mark