Obstruction vs Interference in Fastpitch Softball
The easy way to remember it: the defense obstructs, the offense interferes. Obstruction is a fielder without the ball getting in a runner's way, and she's awarded the base; interference is a runner or batter getting in a fielder's way, and that player is out.
When it comes up
It comes up any time a runner and a fielder end up tangled and you have to sort out whose fault it was. The first question is always: who had the ball, and who got in whose way?
What the call is
One word is on the defense, the other's on the offense.
- Obstruction: a fielder without the ball, not fielding a batted ball, blocks a runner.
- The umpire awards her the base she'd have reached, so it helps the offense.
- Interference: a runner, batter, or base coach gets in a fielder's way on a play.
- That player's out, the ball's dead, and other runners go back.
- Quick test: fielder blocks runner is obstruction; runner blocks fielder is interference.
Why the rule exists
Both rules protect fair play: the defense gives runners a clean path when it doesn't have the ball, and the offense can't bail out a fielder by getting in the way. Deciding who had the right to that spot keeps a collision from becoming a free advantage.
How it changes by age
Defense obstructs and offense interferes at every age; what changes is how strictly it's called, since younger players run into each other by accident a lot.
Test yourself
A ground ball is hit to the outfield. The runner rounding second bumps into the shortstop, who's just standing there without the ball. The runner gets held up. What's the call?
Show the call
Obstruction on the shortstop, and the runner is awarded the base.
A fielder without the ball can't block a runner's path, so the umpire protects the runner and gives her the base she would have made.