You see it all the time, a stolen base attempt, the fielder gets to the base before the runner then drops his knee, foot or leg in front of the base to keep the baserunner from touching the bag. Is this a legal play? What should coaches, players, umpires and fans know about the rule surrounding this defensive move? Chris Welsh and MLB, Umpire, Greg Gibson, discuss this and get you what you need to know about baseball rules.
High School Interpretation
(this is different than the pro (OBR) interpretation)
The interpretation at the high school level is different from OBR. NFHS rules require the fielder to be in possession of the ball before attempting to block the base. The call for violating this rule is obstruction.
NFHS 2-23-3: The fielder without possession of the ball denies access to the base the runner is attempting to achieve.