The 'Threshold' box is the amount of pitches that pitcher was at after he threw the first pitch to the last batter he faced. This is the number that determines his calendar days of rest required by the Pitch Chart. This is an OPTIONAL field, but if you want to use this pitcher in your next game you should include it if it makes a difference in days-of-rest. If your opponent has pitchers at those levels, it would be very helpful to us if you could calculate and enter theirs as well.
NOTE: If you do not enter threshold or anything at all by 9:00pm the next night, OR 6 hours before your next game time, whichever comes first, your records are invalid and we will use your opponents instead.
If you are interested in reading the rule it is on the bottom of page 24 of the Pony Rulebook (CLICK HERE). Page 4 also lists the changes made in the 2020 book, and this is what it says of the change....
RULE: 10-D & T-8-A
RULE CHANGE: The pitcher will only be required to observe the calendar day(s) of rest for the threshold he/she reached during the start of that at-bat, provided that the pitcher is removed before delivering a pitch to the next batter.