Cleveland ? Maybe LeBron James stepped over the line with his allegiance to the New York Yankees.

A day after the Indians routed the Yankees 12-3 in their AL playoff opener Thursday night, the buzz around town wasn’t about Cleveland’s offensive power surge or pitcher C.C. Sabathia’s gutty performance.

Instead, fans jammed sports talk-radio lines and Internet message boards, crying foul over their frustration with the NBA superstar’s traitorous appearance in the stands wearing a Yankees cap.

“The guy is the face of Cleveland sports, and he’s not even rooting for a team that’s 100 feet from the building he plays in,” said Adam Burke, who was waiting outside the left-field gate for Game 2 on Friday.

James’ office, Quicken Loans Arena, sits just across a plaza from Jacobs Field. The Eastern Conference champions are displaying a large banner on the building wishing the Indians good luck in the postseason.

But their All-Star forward, who grew up in nearby Akron, isn’t backing one of his hometown clubs. The 22-year-old, who also roots for the Dallas Cowboys, has worn his Yankees cap around town for years, and last week while in New York rehearsing for “Saturday Night Live” predicted the Yankees would beat the Indians.

Fans have mostly tolerated James’ decision to back the hated Yankees, who have been the Indians’ foil since the 1950s.

But Thursday night’s appearance behind home plate wearing the dreaded interlocking “NY” insignia may have been too much to bear. James not only wore the cap, but he flaunted it, at one point holding it high over his head.

Later, though, as the Indians began to pull away, he put it on backward and left the ballpark holding it in his hands. One fan even offered his Indians cap to James, who slapped hands with others as he exited. Around town, James’ actions caused an uproar.

“LeBron James. King of Nothing. Fan of Yankees. Get Out of Town,” read a sign Friday at a Marathon gas station in suburban North Ridgeville.

“From a PR standpoint, that’s a terrible decision,” said Burke, 20, who doesn’t like that James has distracted from the Indians’ victory. “That’s the sad thing. We dominate every aspect of the game, but LeBron’s dominating the airwaves. Maybe he wants it that way.”

A few blocks away from Jacobs Field, fans still were getting their pictures taken in front of the Nike “Witness” billboard on the side of a downtown office building.

“So what if he wears a Yankees hat?” said Willie Watson of Cleveland. “He wins games for Cleveland.

“So he likes the Yankees. Boo hoo. Big deal. What’s next? We don’t like him because he listens to hip-hop instead of the Cleveland Orchestra?”

Sabathia, who is friends with James, has backed his buddy’s right to show Yankee pride.

“I don’t think it’s that big a deal,” Sabathia said again Friday. “I knew he was coming, but I didn’t know he had a Yankees hat on and stuff. My family told me people were all over him.”