Snake bites

• Gibson said injured right-hander Brandon McCarthy did not throw a scheduled bullpen session Monday because his shoulder felt fatigued.

"He came in and said that he felt fatigued and didn't think it was right to throw a bullpen, and we all agreed," Gibson said.

McCarthy threw a flat-ground session Thursday.

• Injured outfielder Adam Eaton has begun serving as the designated hitter for Class A Visalia as part of a rehab assignment.

• The D-backs' training staff has tried to be proactive in terms of making sure that players stay hydrated during this road trip. In addition, the team did not take batting practice on the field Thursday and will likely skip it again Saturday.

It has been hot and humid in Washington, and more of the same is expected in Atlanta and New York in the final two stops of the 10-game trip.

"It's just different when you're out here," Gibson said. "Your uniform sticks to you, it's hot and you sweat a lot more. We just want to try and attack it right out of the gate, as opposed to playing for a while and saying, 'Oh we're getting tired.'"