It is often the duty of a catcher to stick up for his or her pitcher. Whether that means sticking up for them against the opposing team, the visiting dugout, or even the home plate umpire; it’s what they’re supposed to do.
And while you’ll rarely see a catcher need to prevent an umpire from charging the mound or anything of the sort (rarely, but not never), they will often be confronted about their strike-zone in obvious, non-verbal ways.
Take, for example, what South Korean catcher Jungseo Cho recently did for his pitcher in the Little League World Series against New York:
Clearly upset about the non-strike call, Cho keeps his mitt and the ball completely stationary, well after the pitch. We’ve certainly seen catchers hold the ball there for a moment or two after receiving it, to let the umpire know what he thought of the call, but this is by far the longest I’ve seen a pitch held. In other words, he didn’t just want the umpire to know how he felt, he wanted everyone to know.
To be certain, the pitch was borderline at best, but I could see it being called either way. The umpire, having received the message loud and clear, then calls time to “walk around and dust off the plate,” while clearly telling the catcher, Cho, not to do that anymore.
Cho, now with his mask off, gives a slight smile and a nod, having learned not to piss of the ump. All in all that took some serious guts; but that’s what it takes to be a catcher.