Robinson Cano deposited McCarthy's misplaced changeup into the second section of the left-field bleachers for a three-run homer to help the Yankees beat the D-backs, 4-2, at Yankee Stadium.
When he reworked his mechanics and changed his arm slot a few years ago, McCarthy lost the feel for the changeup, and he's been working to get it back since.
"It's still such a hit-or-miss pitch," McCarthy said. "Sometimes it's there, sometimes it's not. It's very hard for me to get to a place where it can be relied on in a situation. It was coming along; I felt like it was doing what we needed it to do. It just maybe, in that count, it might have been too good a pitch."
The D-backs led, 2-0, after three innings, but while they had Yankees starter Ivan Nova on the ropes, they were unable to deliver a knockout blow.
Similarly, McCarthy was pitching his way into and out of trouble as the Yankees wound up stranding the bases loaded in both the first and second innings.
"I was just completely out of sync and just kind of not able to do a whole lot," McCarthy said. "I felt like I was at least still battling, which is kind of good. I just couldn't get right from the 'pen all the way through. Even after evaluating, I don't know what it is mechanically that I was looking for. Just everything was so off."
Yet he was still ahead. Then came the fourth.
Lyle Overbay and Chris Stewart led off the inning with singles, but McCarthy rebounded to strike out Gardner on a 1-2 changeup that was picture perfect.
The way that pitch was thrown gave catcher Miguel Montero the confidence to call for the changeup when Cano ran the count to 3-2 with runners on first and second.
Montero wanted the pitch away and McCarthy left it middle to middle-in, and Cano crushed it.
"I felt he had a good feel for the changeup, and I just called it," Montero said. "I don't second-guess myself. It was just a bad pitch, regardless."
When McCarthy struggled in his last outing, he said that he and Montero relied too much on hard pitches and did not change speeds enough.
The pair vowed it would not happen again, so Montero called for more of the changeup on Tuesday.
"He threw a couple of pretty good ones today," Montero said of McCarthy. "Obviously, he threw good ones and bad ones. We've got to call that pitch. We can't stay on one pitch -- hard, hard, hard. We've got to throw it and hopefully execute it. It's just part of the game."
Cano is the Yankees' hottest hitter, and the D-backs acknowledged that when they walked him with two outs and runners on second and third in the second inning. That was not as much of an option with runners at first and second in the decisive fourth.
"He got to a 3-2 count, and the ball didn't move as much as he needed it to," D-backs manager Kirk Gibson said. "Even if it does, he's a very good hitter. He got us. We pitched around him early in the game and got away with it, but we had no way out of it this time."
The D-backs were able to chase Nova from the game after five innings, but that was of no help, as four Yankees relievers allowed just one hit over the final four innings.
"They all came in and got everybody out," D-backs designated hitter Eric Hinske said. "That's a recipe for success right there. Late in the game, you've got to try to claw back and score some runs, and we weren't able to. Give them credit. They did a great job."
All players on both teams wore No. 42 jerseys in honor of Jackie Robinson Day, which was officially Monday, when both teams were off. As it turns out, the hero of Tuesday's game was extra motivated to play when he saw the jersey hanging in his locker.
"That was one of the days that I always wanted to be in the big leagues to play," Cano said. "That guy opened the door for us. It's amazing to get a chance to wear 42 that day."