Need help with a rule reference

[buckeyetc71]

FED.
Sit: R3, outs don't matter. F1 makes legal pick off move to third, however, F5 is nowhere near the base (about 20 ft). Throw goes to F5 who moves one step closer to base to make catch of throw. I am BU in C and immediately call balk based on F5 not being close enough to make play on runner. Of course defensive HC comes out to argue, ends up ejecting himself, and we move on.
I cannot find this in the NFHS rule book. Found it in the Case book, pg53, Sit 6.2.4J.
Any rule guru's out there?

Tom C.