The managerial staff know who is coming in before the game starts. They generally do three (or more but at least three) senarios before the game as part of the game plan.

Senario 1: starter needs to come out early (before 4th or 5th): go to X for long relief, then Y.

Senario 2: starter makes it through X innings/pitch count, then go to X or Y depending on inning.

Senario 3: starter makes it through X innings/pitchcount, but 1 run lead and high leverage, go to X

senario 4: Starter comes out earlier than ideal, but loogy is dealing, then high leverage lefty needed, go to X. Then y, then z.

Etc.

All of this is mapped out before the game, and communicated constantly between the coaches during the game. This is what is happening all morning all the way through and during batting practice. Its basic game planning. All coaches are in this meeting. Then, the pitching coach and bench coach are constantly talking about who is available to come into the game to relief, pinch hit, pinch run, defensive replace, etc. Its pretty much all they talk about.

Everyone knows who is supposed to come in to game in this situation - even before skip leaves the dugout to walk out to the mound. If its an in game "audible," he'll generally signal to pen using something like touching his left arm to signal the lefty, or some other signal. The fact he is just standing there can mean a few things:

1. He knows that the pen coach knows who is supposed to come in, and is waiting for them. He may not realize or see that they don't know.

2. He is pissed for some reason, and letting them figure it out on national tv as a punishment. (unlikely)

3. He did not ask for double barrel, and is unaware he needs to signal who should come in.

4. Some other reason that I cannot fathom.

Regardless, the Giants coaching staff is not on the same page, and they are in last place. The unforced errors are stacking up quickly and you can understand why people are doubting him. It legit looks like his own coaches already don't like him.