That left Derek Norris on the bench to start the game, with John Jaso behind the plate.
"John's swinging a hot bat, as of late, and I was riding out a hot bat a couple weeks ago and then piecing together a couple of hits here and there," said Norris.
For the A's, matchups dictate everything, so Norris didn't enter Sunday thinking of it as a day off.
"With the system that we have, there is no such thing as a day off," Norris said. "Just because you don't start a game here, doesn't mean you're not going to play. More times than not, you're going to be an impact player whether you start or not."
With six games on turf looming for Yoenis Cespedes and the A's, Melvin penciled in the Cuban slugger at designated hitter and moved Brandon Moss to cover the hole in left field.
Facing Masterson, the switch-hitting Alberto Callaspo made more sense at first base than new acquisition Kyle Blanks, who will face left-handers.
"With Masterson, we're going to try to get as many lefties in there as we can," Melvin said.
The moves paid off, as Oakland chased Masterson after 4 1/3 innings of a 13-3 win.
Stephen Ellsesser is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.