The following rule will go into effect beginning Monday, May 13th:
NO TEAM MAY ROSTER MORE THAN TEN PITCHERS (not counting pitchers on the IL).

Should you see a team in our league AFTER the aforesaid date with more than ten pitchers, please let your commissioner know. The commissioner will remove the last pitchers added to the team that contains more than ten pitchers. All managers are expected to cooperate, and any manager who violates this rule intentionally will not be invited back for future seasons of play.

You might ask why this rule extends only to pitchers, and not to batters (You are free to roster twenty batters).
Pitchers can be inserted into the lineups on days they are scheduled to pitch, then benched in favor of another pitcher scheduled to pitch the following day. All batters play most days, but only one can fill each batter position slot on any day. Thus I see no reason to restrict managers to ten batters if they want more than ten, and at the expense to them of a pitcher. The unfairness arises from rostering extra pitchers.

Commissioner