Martinez trashed the bullpen. He got nothing from Roark and Gio. What suggests Davey can manage pitchers?
He got lousy hitting from MAT. Brian Goodwin was gone in a flash. Murphy was hurt the first part of the year, and limped when he returned, and Dave put him at 2B. Neither Ryan Zimmerman nor Matt Adams are so superior than they cannot be moved.
Baker was (and is) literally unhirable because of how he handled pitching.
