On Deck Batter Interference?
 

Popup in foul territory. F5 comes to make play. Runs into on-deck batter who has not moved from his spot.

What are we looking for to determine interference?

Not sure if there are differences between rulesets off the top of my head, but OBR 6.05(o) with the note directing you to 7.11 should cover this situation what to look for in this case.

If I'm calling the game, you can look for me to declare dead ball, call the batter out and return any runners to their bases at the time of the pitch.

For Fed, the rule is 7-4-1-f.

what you are looking for is if he interferes.

no intent required, 7-4-1-f requires all members of the offensive team except runners to avoid interfering with the fielder fielding a foul ball.

requirements for runners are a different rule, not trying to imply they have free reign to interfere.

Did F5 have a play? That's all you're looking for here.