There is some merit to the argument. Injuries to Roy Halladay, Ryan Howard, Chase Utley, Carlos Ruiz, John Lannan, Mike Adams, and others certainly have affected the Phillies' season. Even where those injuries might have been predictable - Halladay, Utley, Howard - the players' contracts made it impossible for Amaro to do much about them preemptively.
So when it comes time for his annual review with Montgomery, Amaro surely will list those injuries as a big part of what went awry. That will sound much more convincing if Amaro hasn't scapegoated Manuel along the way.
The second reasons are connected, but sound like opposites.
Put one way, Amaro hasn't earned the right to fire Manuel. Manuel won a World Series as a manager. He has earned a level of respect for that accomplishment, even if it's sometimes hard for disappointed Phillies fans to remember that.
Amaro took over as GM after the 2008 World Series. We can discuss and debate his various moves, but there is no getting around the fact that the team has gotten worse each of the last two years on his watch. Not just diminished results in the postseason - that began in 2009 - but worse in terms of talent.
Ty Wigginton and Delmon Young, Chad Qualls and Chad Durbin, John Mayberry Jr. and Laynce Nix. These are the players Amaro brought in to complement the core group. If the core had remained healthy and productive, that might have been sufficient. It didn't and that isn't.
Put the opposite way, Amaro knows that firing Manuel would shift the magnifying glass to him. For a GM, a manager or head coach is like a human shield. Once you remove him, you completely expose yourself.
The third reason Amaro shouldn't fire Manuel is track record. Under Manuel, the Phillies have a history of playing better in the second half of the season. To have any hope of salvaging 2013, that is what they must do.
It would be different if you believed the team would be jump-started by a change. But seriously, this group? No one who has followed the steady-pro approach of Howard, Utley, Jimmy Rollins, Cliff Lee, and the rest can possibly believe they will somehow be motivated by a change in managers. It is just not in this team's DNA.
That leads us to the third reason Amaro won't pull the trigger. If he does replace Manuel with Ryne Sandberg and the team stumbles through an even worse second half, then what? Amaro will look even worse, having provided a mediocre team and then scapegoating a good baseball man to deflect blame.
Meanwhile, those fans in love with their idealized vision of Sandberg as a double-switching, player-motivating maestro will have two or three months to see his faults and shortcomings. And even if he's very good, he'll have both.
So you let it play out. If this team rouses itself for a second-half run, it is as likely to do so under Manuel as anyone. If that happens, everyone is happy.
If the mediocrity continues through Sept. 29, Manuel's contract expires. Amaro can make the case to his bosses that it's time for a fresh start. Sandberg (or whoever) can take over at the beginning of spring training with a retooled roster.
And if that roster isn't better, it isn't going to matter who the manager is. All eyes will turn to Amaro.
Contact Phil Sheridan at email@example.com. Follow on Twitter @Sheridanscribe.