Pendleton, who spent six seasons as McCann's hitting coach with the Atlanta Braves, said during an interview with the New York Post that the star catcher will "never be comfortable" playing in New York.
"New York is not Brian," Pendleton told the Post before Atlanta's game Monday against the New York Mets. "That's my opinion. I knew if he chose New York, there would be more than he expected or knew about. He'll never be comfortable with that."
On Tuesday, McCann disputed Pendleton's assertions.
"I read the article. I disagree. I absolutely love it here. I've got off to a slow start, but I absolutely love it here. It's his opinion. That's all I can say, it's his opinion on it," he said.
McCann signed a five-year, $85 million deal with the Yankees this past offseason after spending his first nine seasons with the Braves. The 30-year-old is batting just .230 -- 44 points below his career average -- with 10 home runs and 38 RBIs in 79 games this year.
Pendleton told the Post that he believes the move from Atlanta to New York has been rough on McCann, an Athens, Georgia, native. Pendleton also cited the lucrative contract as one of the reasons for McCann's prolonged slump.
"Going from Atlanta to New York is a different animal," Pendleton said. "Brian McCann is going to put more heat on himself and for him, trying to do more is the worst thing for him. I've learned that. ... That money is hanging over his head. A lot of guys say, 'I've got to live up to that,' instead of, 'They signed you to play your game.'"
Asked Tuesday if the contract was weighing on him, McCann said: "Not at all. Not one bit."
"I really haven't noticed a big difference [between playing in New York and Atlanta],'' he said. "It's still baseball. It's still you put a uniform on, you go out and put your best foot forward. That's what I'm doing. It just hasn't gone quite like I wish it would, but at the same time, we've got a whole half of baseball left. We're in a pennant race and those are the things that I'm focused on.''
Yankees manager Joe Girardi said he "didn't think too much" about Pendleton's comments.
"Everyone's entitled to their opinion. Sometimes it takes people a little time to adjust [to New York]," Girardi said Tuesday. "But I think people are just looking at his average when they're talking about his numbers. But I think from a production standpoint he's been pretty decent. He's done a great job behind home plate with our pitching staff. You put all those things together and yeah, he's not hitting .280, but he's played pretty well.
"I think he'll be fine. I don't think it will be an issue. I think he loves it here. I think he enjoys playing here. And I think Brian expects a lot from himself. So people expecting a lot from him is not going to bother him.''
Pendleton told the paper that he had thought McCann would sign with the Texas Rangers instead of the Yankees, claiming that the seven-time All-Star would be "more comfortable in Texas." But he also thinks McCann will bounce back offensively at some point.
"I think he will become accustomed to [playing in New York]," Pendleton said. "He has to relax and do what he's capable of doing. He said he's not a .220 hitter, and he's right. He's definitely better than he's shown. He just has to settle down."
Pendleton was Atlanta's hitting coach from 2002 to 2010 and has served as the Braves' first-base coach since the 2011 season. The former National League MVP also attributed McCann's tendency to pull the ball as a reason for his slow start, pointing to opposing teams' willingness to shift defensively against him.
"He became a pull hitter over the last three years or so," Pendleton said. "When he got to the big leagues, he hit the ball everywhere. That's what made him so good.
"[Defensive shifting] does affect him because last year he was getting [ticked] off because base hits were going right to the second baseman. I told him to hit the ball to left field, and he'd do it a couple of times, but he had it in his head he wanted to pull. ... If you've got pull on your mind, it doesn't matter how far the fences are back. He's going to pull. That's his mindset right now."
ESPNNewYork.com's Wallace Matthews contributed to this report.