"That was fantastic," D-backs manager Chip Hale said. "We know this guy can hit, he just needs the at-bats, needs to get comfortable. He picked a good time to hit his first home run for us."
Mets starter Bartolo Colon cruised through the first six innings and looked like he might make it seven before Chris Owings singled with two outs and Castillo followed by hitting the first pitch just over the wall in left for his third homer of the year.
"Bartolo Colon is a guy that throws a lot of sinkers," Castillo said. "He's a groundball guy and he keeps the ball down and I saw on that one that he left it a little bit up and middle in and that was the pitch to hit and I hit it out."
It was a nice bounceback game for Castillo, who had made his first start behind the plate for the D-backs on Friday night and struck out four times.
Castillo began the season with the Cubs before being traded to the Mariners and then the D-backs. In his prior two stops, playing time behind the plate was hard to come by. In Arizona, though, that figures to be different as the D-backs will split time between Castillo and Jarrod Saltalamacchia.
"I wasn't playing very much on the other team I was with and now I have the time to play here and I think my rhythm was going to be better at the plate," Castillo said. "Really excited, especially with the type of guys that this team has. Everybody here likes to have fun and go out and play hard. I'm enjoying it."
The D-backs will certainly enjoy their new teammate if he keeps driving in big runs.
"He seems like a real fun guy," D-backs outfielder A.J. Pollock said. "It just seems like he enjoys the game of baseball. He came up there and came through for us and he did it at a time when we really needed to get something going on offense. Hopefully he's got that clutch factor going all year."
Castillo's biggest challenge will come in learning the pitching staff, but Saturday's starter Chase Anderson praised Castillo for how he called the game.
"It's not easy, honestly, because I have to get to know everyone, what their pitches do, what kind of pitch they can throw behind in the count," Castillo said.