COSTA MESA, Calif. -- Philip Rivers was bleeding.

Nothing unusual. It was just before halftime of an otherwise unmemorable Monday Night Football game, and the medical staff was more than ready to tape up the quarterback's wounded arm.

"This s--- happens all the time," Rivers said, heading toward the sideline.

Wait, did Philip Rivers, the NFL's all-time king of fiery but 100 percent G-rated clean trash talk just ... swear?

That's what David Chao thought he heard. Chao worked as the Chargers' team doctor from 1997 to 2013; he and Rivers talked about the incident recently on a podcast.

Chao chuckled about the incident with Rivers' teammates the next day, then heard them getting after their quarterback in the training room, despite Rivers' vigorous objections.

"They were giving him grief -- you know how guys are -- because they sensed that he was sensitive about this," Chao says. "So I was brought in as a witness."

Ever the colorful personality (a bolo tie aficionado, father of nine and eternal chatterbox), Rivers clearly takes pride in his aw-shucks demeanor. Sixteen seasons into his career, he's renowned for his uncanny ability to talk trash without cussing during tense moments on the football field.

"I thought I heard you say the word 's---,'" Chao testified. "But I don't even know that it's a swear word."

"No, no, I didn't say that," Rivers retorted. The Alabama native sticks "shoot" into just about every sentence he says. (And on the field, he says it a lot.) So that alone might have been enough of a defense. But Rivers wasn't done, Chao says.

"Literally, he texted me three times about it afterward, telling me that I misheard him."

YOU DON'T NEED to look far to learn how the NFL's king of clean trash talk came to be.

"I must admit I had some fire with me on the sideline when I was coaching," Philip's dad, Steve Rivers, says of his longtime high school coaching tenure in northern Alabama, where a young Philip played the role of ball boy and manager.

"And so he saw some of that in me, and I had some of that. And I still have it."

Philip picked up the theatrics early. At 4 years old, he was already a crowd favorite for his antics at Decatur High School basketball games. Next to his mother, Joan, his feet tapping to the beat of a drum, his head swaying with the music, Rivers had an act during timeouts.

"We had a pep band," Steve Rivers says. "And he would stand up and be the conductor, sitting by us in the stands and leading the band. He'd be waving his arms and all of that. That's just the kind of personality he had."

The Rivers clan was devoutly Catholic -- and still is: Philip and his wife, Tiffany, got married in college and have seven girls and two boys, so the politeness often came with the territory.

"Definitely he was taught that from the beginning," says Philip's mother, Joan, who works as a middle school teacher at St. Ann Catholic School in Decatur, Alabama. "My family has never used bad language. ... You want to set a good example for the next generation because you're a teacher. So that's part of that as well."

Joan Rivers also comes from a family of seven girls and two boys. And her father -- Philip's grandfather -- does too. Family and faith was important to Joan Rivers growing up, something she passed down to her son.

"He's a strong, religious Catholic and a strong person," Steve Rivers says. "He just tells the truth. He's not trying to hide anything, and that's worked well for him. And as far as his on-field behavior and all of that stuff, he's just having fun."

That audacity served him well in his transition from coach's kid to rail-thin true freshman quarterback at NC State.

"He always had that confidence, that brashness about him," says Norm Chow, former Wolfpack offensive coordinator. "And it allowed him to be successful. He's a bright guy."

The lanky Rivers, listed in high school at 6-foot-5, 215 pounds, grew literally and figuratively into the position, starting 51 straight games in college and earning ACC Player of the Year honors as a senior.

During a game against rival North Carolina in 2000, Chow drew up a trick play in which the freshman Rivers hauled in a touchdown on a receiver reverse pass to put the game away. But mostly the coach remembers the young signal-caller chirping at the Tar Heels.

"He's over there yelling at the other side," Chow says. "And they had some really good players over there like Julius Peppers. And I'm thinking, 'Hey, you young punk freshman -- you're going to get beat up.' But he's yelping at them and pointing at them, guns firing. ... I don't think it was done in any harmful kind of way. I just think he enjoyed playing. And he's still that way."

Yes, even two decades later, the chattering 37-year-old Rivers is still rankling opponents and inspiring teammates with his uniquely squeaky-clean smack talk.

"He loves it," says longtime Chargers center Nick Hardwick. "It's like I imagine he started talking trash when he came out of the womb. It's just in him."

SHAWNE MERRIMAN WENT straight to it when asked how he felt about Philip Rivers before he became Rivers' teammate in 2005.

"I absolutely hated Philip," he said. "Everything about him."

The two were college rivals -- Merriman also played in the ACC, at Maryland -- and the linebacker remembers Rivers grabbing at his legs and pushing off him to get up after a big hit, in addition to his usual jawing.

So when Merriman first encountered Rivers as a teammate on the practice field his rookie year, the former Charger had one mission: coax Rivers into PG-13 language.

"One day I almost did. I thought he dropped the F-bomb, but he didn't," Merriman says. "I think he said 'mother-fudge' or something.

"I got under his skin, and after practice he started to imitate my walk to get back at me. And he can do my walk exactly down to a T. So I never got him to curse, but that day I almost did, and it became a running joke where if we had a great day on defense, he would start to walk like me after practice to get under my skin."

In those early days, LaDainian Tomlinson found a kindred spirit in Rivers -- one whose yelps of "shoot" and "dadgummit" needed no translation.

"I understood it because of obviously our connection of being from the South, and that's just the way people talk, like country folk," says Tomlinson, a Texas native. "So I understood him, and we kind of had a connection in that way."

The Hall of Fame running back says he knew Rivers was the right man for the job during the quarterback's first season as a starter when he stood up to a Denver Broncos defense led by linebackers Al Wilson and Ian Gold.

"They started talking to him, and that was kind of the first time we ever seen Philip jaw back at somebody," Tomlinson says. "And when we did, we all kind of looked at him and said, 'OK, this dude's going to be all right. He's not going to put up with that.'"

That reputation grew quickly over the course of Rivers' time as the starter, a job he has held since 2006, with the fiery quarterback at the center of several memorable encounters.

"There's obviously games and a history you have with guys that maybe you're a little more fired up to let them know if maybe you beat them on a play," Rivers says of the method to his madness. "And then there's others where you go, 'It ain't worth fooling with. I think it's kind of on the back burner.'"

There were the dustups with fellow QB Jay Cutler, whom Rivers famously shouted off the field after a turnover on downs in 2007; the end-of-game shouting match in 2011 with the usually quiet pass-rusher Von Miller; and just last year in the playoffs, a poignant "That's what you get!" aimed at the Ravens' Matthew Judon after the linebacker injured himself on a late hit.

Ask around the league and the quarterback's friends and foes alike will dish their opinions almost as quickly as Rivers will giddily needle opponents:

Hardwick: "He's such an instigator. And it's super hilarious having a quarterback that you're trying to protect from some of the baddest dudes on the planet from trying to kill him. And he's trying to provoke them to get them to try to kill him more, which makes your job more challenging."

Merriman: "People can say whatever they want, and it's no knock on Drew Brees' greatness or the things he accomplished and him being a great quarterback, but I would rather play for Philip any day. We played with a certain swag in how we approached the game, and Philip was always right there along with us."

The Broncos' Miller: "If you're losing, it's going to suck. But if you're in a tight game and you're winning, it's fun. It's good to get some type of personality out of a quarterback. ... I've said it before: If he was on other teams where other elite quarterbacks were, he would have some of that same success -- he would have multiple Super Bowls too."

Niners cornerback Richard Sherman: "I messed with him about his bolo a few times, but nothing crazy. It's family friendly. A lot of times he's just fired up, like, 'You can't stop us!' or 'You're not gonna stop us today,' and he's just going. But never anything vulgar or anything even super negative. You can always mike him up and never worry about it."

Colts edge rusher Justin Houston: "He talked some trash, but most of the time he's yelling at the refs. The conversation I really had with him one time was about his cleats. He was wearing some real old Reebok cleats, and Reebok doesn't even make cleats anymore, so that tells you how old they were."

Colts coach and former Chargers offensive coordinator Frank Reich: "I love to see him in that mode. It's just coming from the right place: He loves the game and is passionate about the game. And I think that stems from how hard he prepares. I think that stems from how much it means to him. I think it stems from how much his teammates mean to him, that it's important to him. So I certainly have loved watching it over the years."

RIVERS HAS ALREADY begun transitioning to life after football.

He wants to follow the example of his father and become a high school coach, and his good, clean enthusiasm has already come in handy as offensive coordinator of his oldest son Gunner's flag football team.

"Certainly when we're playing, whether it's trying to get a call from the refs, putting in a little word here or a little word there," head coach Don Cella says. "Which is ironic because you would think we would get a lot of calls, but it feels like a lot of times we end up getting the short end of the stick, almost like we're going to make sure that Philip Rivers doesn't get the calls.

"There was this one coach in particular that called out a play that he thought we were going to run, and we ended up running it and we scored on it," Cella remembers, laughing. "And [Rivers] was like, 'You can call it, but you've still got to stop it!'"

Even with his offensive coordinator still in the final year of an NFL contract at his day job, Cella says he enjoys watching the interaction between Rivers and his son.

"He's awesome," Cella says. "He's tough on him. He has high expectations with Gunner, but it's in a good way. ... He will pull him aside and ask, 'What did you see here?' or 'What did you see there?' 'On this route combination, who are you reading?' So it's like he's that QB coach with him, but every now and then you just see that raw emotion and passion when Gunner makes a big play."

"Who knows what will happen," Rivers says of coaching Gunner, whose distinctive three-quarter throwing motion looks awfully familiar. "But he does have an ability to anticipate and throw things early. And I don't know if you can coach some of that. Some of that is God-given, so it's going to be fun to see what kind of player he turns into."

AFTER A RECENT practice at the Air Force Academy in preparation for the altitude his team will face in Monday's game against the Chiefs in Mexico City, Rivers playfully recalled his alleged s--- slip with Chao, the lone mark on his spotless G-rated record.

"I still deep down believe that I don't think I did it -- and it's not because I'm trying to be so righteous that I didn't say it," Rivers said. "But I don't think I did."

That doesn't surprise Chao, who jokes with Rivers about the legend of his purported profanity to this day.

"I think it completes the picture of what kind of guy he is," Chao says, offering some other reasons he admires the quarterback. "He isn't doing any of this for the cash; he's played through a number of injuries that the public has never known about. ... He's just that kind of guy."

And Rivers, the NFL's foremost dad, its immaculate instigator, is sticking to his story.

"At the end of the day, if I did slip up, I slipped up, you know what I mean? But I still tell Chao to this day, I think you misheard me because it's not in my vocabulary."

ESPN NFL Nation reporters Nick Wagoner and Mike Wells contributed to this report.