They've followed him from his days with the Red Sox, and Millar always receives the same reaction from New York fans when he steps up to the plate as an Oriole.
But that's how he likes it.
"It's fun, I enjoy it," Millar said. "I love it. I'm not a good enough player to boo, because usually they only boo good players, but coming in here is fun. I always told the Yankees fans, 'Don't be nice to me, boo me.'"
And given his numbers against the Bombers, maybe Millar is onto something. Maybe the jeers are helping.
When he connected on a solo home run in Tuesday's contest against the Yankees, it marked his sixth homer against New York this season -- the most by any Bombers opponent this year.
Step aside, Manny Ramirez. There's a new Yankee killer.
With 21 homers, Millar has slugged more career home runs against New York than against any other opponent. He knew he'd belted a few against the Yankees this year, but Millar said he didn't know the exact numbers.
Orioles manager Dave Trembley said Millar's success could probably chalked up to a combination of the status of the opponent and chance.
"I'm sure guys enjoy playing against the best teams, so there's some incentive to do well," Trembley said. "And I also think it's coincidence."
Millar didn't have an explanation, either. But he had the opportunity to light up Yankee Stadium again in the series finale Wednesday afternoon as the Orioles looked for the sweep, facing off against Joba Chamberlain.
"The thing about it, the Yankees have been a great team and they've always had great pitchers," Millar said. "It's been a great rivalry. I've always been a part of it the last few years, so it's been fun."
Samantha Newman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.