Richard Sherman's brash postgame rant generated national buzz Monday, with reaction mostly ranging from shock to outrage.

But those who know the hypercompetitive Seattle Seahawks cornerback best weren't surprised by his 15-second tirade targeting 49ers receiver Michael Crabtree.

"That's Richard," said Stanford coach David Shaw. "It was in the moment."

Sherman became unhinged after his leaping deflection of a pass -- it was intended for Crabtree in the end zone -- sealed Seattle's Super Bowl-clinching victory Sunday evening.

A day later -- after an epic NFC Championship Game that featured NaVorro Bowman's gruesome knee injury and Colin Kaepernick's fourth-quarter turnovers -- Sherman's words echoed loudest throughout the Bay Area.

Seattle Seahawks’ Richard Sherman (25) holds up the NFC Championship trophy after they beat the San Francisco 49ers 23-17 for the NFC Championship
Seattle Seahawks' Richard Sherman (25) holds up the NFC Championship trophy after they beat the San Francisco 49ers 23-17 for the NFC Championship Game at CenturyLink Field in Seattle, Wash., on Sunday, Jan. 19, 2014. (Nhat V. Meyer/Bay Area News Group) ( Nhat V. Meyer )

The loquacious Sherman, who graduated from Stanford with a degree in communications, is usually refreshingly candid in a cliché-dominated sports-media culture.

But occasionally, Sherman's internal braking system malfunctions and the massive chip on his shoulder -- the chip that fueled his rise from Compton to Stanford to the Pro Bowl -- is exposed for the world to see.

"Bill Walsh said you want guys with high character who are great players and great people," Shaw said.

"But every once in a while, you have to line up and defend Jerry Rice. And the guy who does that has to be on the edge. That's where Richard is."

Sherman, who bragged about being the NFL's best cornerback and called Crabtree a "sorry" and "mediocre" receiver, apologized Monday and expressed regret during an interview with ESPN radio.

"Obviously I could have worded things better and could obviously have had a better reaction and done things differently," he said. "But it is what it is now, and people's reactions are what they are."

Seattle coach Pete Carroll, who met with Sherman on Monday, said his cornerback also was contrite about taking attention away from his team: "He was really clear that the last thing he wanted to do was take something away from our team, what we had accomplished."

Had Sherman swatted away a pass intended for any other 49ers receiver, the tone of his comments would likely have been drastically different.

But his dislike for Crabtree is intense, and the feeling appears to be mutual.

"They have a personal vendetta against each other," said Sherman's brother, Branton.

The animosity stems from a charity event last summer hosted by Arizona Cardinals receiver Larry Fitzgerald. Sherman saw a group of people, including Crabtree and Snoop Dogg, sitting around a swimming pool. He went over to shake hands.

"When he got to Crabtree, Crabtree slapped Richard's hand away and stood up like he wanted to fight," according to Branton Sherman, who learned about the incident from his brother.

"Everyone was like, 'Calm down, Crabtree.' Richard said, 'Why are you tripping out. We're off the field.' Crabtree wanted to fight but everyone got in the way and backed him down."

Former 49ers receiver Kyle Williams attended the event.

"I'm not going to get into specifics," Williams said. "Those guys (Richard and Branton Sherman) can say whatever they want.

"To me, what happened (Sunday) was nothing more than two guys who are passionate about what they do and are at the top of their games at their respective positions.

"Richard called him out 100 percent. (Crabtree) will respond. He'll work hard and make sure he's ready to respond on the field."

Crabtree declined interviews Monday, but several 49ers addressed the incident. Linebacker Ahmad Brooks said Sherman was "just hyped up," while tight end Vernon Davis suggested that Sherman needed to learn "how to be a true gentleman that shows good sportsmanship."

Sherman, who authors a first-person column for Sports Illustrated's website, addressed the situation Monday:

"It was loud, it was in the moment, and it was just a small part of the person I am," he wrote. "I don't want to be a villain, because I'm not a villainous person."

Raised in Compton, surrounded by street gangs, Sherman was a straight-A student who took Advanced Placement classes, attended leadership seminars and finished second in his class.

The son of a garbage truck driver and a social worker, he became the first Dominguez High School graduate in the past half century to receive a football scholarship from Stanford.

The 24th cornerback picked in the 2011 draft, he now stands as one of the most dominant defensive players in the league.

The lesser-known side to Sherman, 25, is his relentless commitment to community service.

His charity, Blanket Coverage, has raised approximately $100,000 for inner-city schools since its launch in April, according to Branton Sherman, who runs the organization.

Shaw, who remains close friends with Sherman, recalled asking Stanford players for volunteers to attend Football Camp for the Stars, a San Jose-based event for athletes with Down syndrome.

"Richard was the first to raise his hand," Shaw said. "He was there at the beginning, and he stayed past the end.

"He is the farthest thing from a thug you can imagine. Thugs don't volunteer to help out at Special Olympics when they're in high school.

"But the flip side is a guy who's ultracompetitive. You put him in that environment, where the game is very personal, and when the gauntlet's thrown down, he's ready."