Illegal Defensive Substitutes

 
In MCBA, the coaches do not report defensive or offense substitutions to the UIC. However, what are the penalties if the offensive coach raises questions about a defensive player's eligibility?
 
Each situation below assumes that each team has 12 players, but started the game by batting 9 with 3 substitutes:
 
1. In the middle of bottom of the 4th inning, the offensive coach notices that there is a new first baseman on the field (#23), but the offensive team has not been notified. The defense coach reacts by yelling "the first baseman on the field (#23) is a replacement for a starter (#57), who is on the bench".  What should the plate umpire do now?
 
Call
There is no penalty against the defensive team. As long as #23 could legally enter the game for #57, he is considered an unannounced, but legal, substitute and may stay in the game on defense.

 
2. In the 3rd inning, #47 was an announced substitution and batted for #14. In the middle of the bottom of the 5th inning, the offensive coach notices that #47 is playing first base and #14 is catching. What should the plate umpire do now?
 
Call
In this case, #14 is an illegal substitute. #47 is legally in the game and may continue to play defense. #14 is removed from the field immediately and is restricted to the bench for the rest of the game. Note that if #14 made a play as an illegal substitute, you cannot retroactively change the outcome of that, or any other, play.