Are you kidding me?
This is a very interesting -- or, you could say, horrible -- move by the D-backs. Can you say, "trigger finger"? Sure, the D-backs have the third-worst record in the MLB, but it's not Byrnes' fault his ace Brandon Webb has been on the disabled list all season. Or that Chad Qualls doesn't know how to nail down a save. Or that Conor Jackson has been non-existent.
Odds are Byrnes will get a GM job elsewhere, but I'm sure Theo has already sent him a text with an opportunity to come back home, for at least the duration of this season.