Follow-Through Interference

 
There are no outs and the runner on first base (R1) is stealing on the pitch. The batter (B1) swings hard at the 1-1 pitch, misses the pitch, but B1's follow-through hits the catcher while the catcher is attempting to throw out the stealing R1. R1 is safe at 2nd base.  
 
What does the umpire do now?
 
Call
In NF (and only NF), it is follow-through interference when the batter's bat hits the catcher after the batter has swung at the pitch -- and the batter's action interferes with the catcher's attempt to make a play on a runner. The penalties are enforced as batter's interference and detailed in NF 7-3-5. In the situation below, B1's follow-through interference is penalized as batter's interference (NF only, 7-3-5 and Casebook 7.3.5J). B1 is out and R1 is returned to first base.