The DP can play defense for any fielder, other than the flex and it is nothing but a defensive position change and there is no need to report it to the umpire, unless they are pitching and then simply because the pitcher is eligible for a courtesy runner. When the DP plays defense for anyone other than the flex no one has left the game and there have been no substitutions. If the DP does play defense for the flex, then the flex has left the game and must use a reentry to come back into the game. The same is true if the flex bats or runs for the DP, then the DP has left the game and must use a reentry to come back.I have a hard time wrapping my brain around all of the possibilities with dp /flex amd I only used it in the most simplistic way over the summer. (Neither of my two main pitchers hit for various reasons.)
Saw this in a game. Coach using dp/flex for his pitcher. The third baseman got too much heat. DP goes in to play defense at third. 3b doesn’t play defense but still hit.
What happened there? Is it just a defensive substitution that doesn’t need to be reported? It’s not a substitution, right?