According to an article on the club's website, the two Diamondbacks' starting pitchers developed a friendship while teammates on the Oakland Athletics. When McCarthy arrived in Oakland he set out to make friends with the reserved Cahill, trying to break him out of his reserved shell. "That helps break the ice, and we just become friends," McCarthy said.
The two starters apparently continued their friendship, taking vacations together with their significant others and texting frequently when they were no longer on the same team.
"It really did hurt when he left," McCarthy said about Cahill's trade to Arizona before the 2012 season. Now the two will be back in the same rotation with Arizona.
"Having him as a friend really helped us as teammates in Oakland, though," Cahill said. "Getting input from a friend instead of just another player kind of gives you another perspective on how to work on things, like if something is going badly or needs to get switched up."
Cahill, McCarthy and the rest of the Diamondbacks begin Spring Training in early February.