That's because Mattern, who serves as sergeant-at-arms for Ravens Roost 71 in Middle River, actually grew up a Steelers' fan. On typical Sundays he wears a Joe Flacco jersey, and he once had his beard painted purple. But when kickoff rolls around, he'll be serving up chicken at a Royal Farms store, where he works as an assistant manager, wearing a Ben Roethlisberger jersey beneath his work shirt.
For many people in Baltimore, Mattern's attitude is unfathomable. They seethe with hatred for the Steelers. When the two teams meet, it's always a big game. It's even bigger this time. Perhaps the biggest game of the season, and here's why:
•Both teams are 8-3 and tied for first place in the AFC North. A Ravens victory essentially gives them a two-game lead in the division with four games left to play because they would have beaten the Steelers twice this season.
•It's nationally televised by NBC, which gives the city a chance to shine in front of a huge audience. NBC's "Sunday Night Football" is the highest-rated prime-time sports franchise in TV history – both in overall audience and the key demographic of viewers 18 to 49 years old. This fall, it became the first weekly sports program to ever be the highest-rated series on television.
No less an expert than Al Michaels, the veteran play-by-play announcer who spent 20 years in the booth with "Monday Night Football" before joining NBC's Sunday night team, says Ravens-Steelers is "definitely one of the biggest games of the year. This has become a great rivalry — very intense, very physical. It's pretty much the NFL's answer to a cage match. That's what it's become. These are two teams that are not fond of each other."
NBC sports analyst Rodney Harrison concurs.
"When I saw the schedule come out this summer, I was really excited," said Harrison, who played for the San Diego Chargers and New England Patriots and was a two-time Pro Bowl selection at safety. "This is the most physical game of the year. You have two of the best young quarterbacks in the game facing each other. The two most physical defenses in the game, and you have the two best linebackers in Ray Lewis and James Harrison. …You have all the subplots."
•Everyone wants to be in the crowd at M&T Bank Stadium. The game is a sellout and tickets on the secondary market are going for $600 apiece to sit behind the Ravens' bench or $200 for upper deck seats, according to Stub Hub and other websites.
•Local bars and restaurants will be brimming with fans who can't get into the stadium, and those people will be spending freely, especially if the Ravens win.
Mattern understands the subplots, and usually sees the Ravens' side of them. But don't ask him to back Baltimore when the Steelers are in town, even if it's the biggest game of the season.
"They were the first team I was introduced to," said Mattern, 37, whose parents hailed from Pittsburgh. "I'm a Steelers' fan first, and I don't mind sharing that."
Mattern's brethren in the Ravens Roost fans organization have come to terms with his conflicting passions – though they did vote to ban his wearing Steelers' garb to their meetings.
"We give him hell for being a Pittsburgh fan when the Steelers come to town, and he goes along with the torment," said Mel Topa, president of the Council of Baltimore Ravens Roosts.
"Ray is a freak of nature, in a good way," said Dave Abeshouse, president of Roost 71. "I thought he was putting me on, the first time I saw him in his Steelers' shirt.
"We accept him because it's impossible to dislike him. If he was a jerk, we would have cold-shouldered him or thrown him out, but he's got a big, big heart."
Mattern is the group's team captain for the Polar Bear Plunge into the Chesapeake Bay in January, an annual benefit for the Maryland Special Olympics. He'll get wet again at the Ravens' Roost convention in June where, for three years running, Mattern has sat in the dunk tank, in a Steelers' shirt, getting doused to raise funds for the organization.
"Every year, the line of people waiting to dunk Ray gets longer," Abeshouse said. "That's how hostile Ravens' fans are toward the Steelers.
"Once, Ray called a timeout (after 20 minutes in the tank) and changed from a Heinz Ward jersey to a Roethlisberger one," Abeshouse said, describing a switch from the jersey of the Steeler's star receiver to that of its notoriously slippery quarterback. "People went nuts. You can't believe the abuse he took, wearing (the colors) of the two most hated Steelers."
Who wouldn't shell out a couple of bucks to dump those guys in the drink?
"We made a lot of money for charity that day," said Abeshouse.
Last year, at the convention's parade in Ocean City, Mattern stood on a float, in a Roethlisberger jersey, and let himself get "knocked out" by Ravens' fans wearing boxing gloves.
"Yeah, I took a dive," he said. "Oh, the sacrifices I've made for this team."
As he sees it, Mattern isn't really a turncoat. Early on, he said, the Ravens had several ex-Steelers in their lineup — running back Bam Morris, tight end Eric Green and Rod Woodson, the Hall of Fame defensive back.
Mattern's favorite Raven? Flacco, who else?
"He started out at the University of Pittsburgh," he said.
Heading into Sunday's game, the Ravens are considered a slight favorite. Most betting lines have them winning by a field goal.
As a fan of both teams, Mattern's prediction for Sunday might hold credence. His thoughts?
"The Steelers will take it, 17-14."
Baltimore Sun reporter David Zurawik contributed to this article.