So I have a prospect that has these pitches... P1:67 / P2:83 / P3:40 / P4:55 / P528. Will he be less effective than if his pitchers were re-ordered to: 83/67/55/40/28?

The second set of pitches would be more effective.

Would a high PC catcher help combat some of this?

PC is a modifier. Higher PC always helps pitchers.

Posted by tecwrg on 4/28/2017 11:11:00 AM (view original):
The second set of pitches would be more effective.

What's this based on, tecwrg?

EDIT

To be clear, it may well be true, but I'm curious what source you're relying on because it is one of the things that the (now *really* old) developer chats went back-and-forth on.

See, e.g., https://www.whatifsports.com/devchat/devchat.asp?chatid=74

Why would a pitcher's best pitch not be his P1? If his P2 is a better pitch should he not use it more than his lesser P1? (bourbonmoon - Hall of Famer - 2:24 PM)
The pitches are not ranked, so pitch 1 is not always or supposed to be better than pitch 2.

Compared to https://www.whatifsports.com/devchat/devchat.asp?chatid=94

In a theoretically identical situation (catchers, fielders etc..) would a pitcher with pitches of 90-80-70 be expected to perform identically as a pitcher with pitches of 70-80-90? Or does the pitch order matter? (sickchangeup - Hall of Famer - 1:29 PM)
The pitch order matters, but not that much. The first pitch is his out pitch.

Admin has confirmed that the order of pitches matters.

P1 > P2 > P3 > P4 > P5.

Posted by tecwrg on 4/28/2017 2:29:00 PM (view original):
Admin has confirmed that the order of pitches matters.

P1 > P2 > P3 > P4 > P5.

Any documentation beyond the developer chats (which say both things) in my edited post?

My customer support ticket: "If I had two identical pitchers in all ratings, but one's pitches #1-3 were rated 65-63-70 and one was 70-65-63, would they be of identical quality? Do they use their best pitch most often, or their P1 most often, regardless of rating?"

CS Answer: "Pitch 1 holds a greater impact than pitches 2 or 3. Pitch 2 would also hold a greater impact than pitch 3. There might not be much of a difference in the hypothetical situation you laid out above."

FWIW.

Posted by zbrent716 on 4/28/2017 3:01:00 PM (view original):

Posted by tecwrg on 4/28/2017 2:29:00 PM (view original):
Admin has confirmed that the order of pitches matters.

P1 > P2 > P3 > P4 > P5.

Any documentation beyond the developer chats (which say both things) in my edited post?

My response was based on the Dev Chats you posted.