LOS ANGELES -- It would've been hard for anyone to talk about with a straight face. Mariano Rivera of the New York Yankees is the greatest closer of all time, not some guy you watch on tape and try to pick up a few insights from. And certainly not some guy you say you're trying to emulate.
"I don't want to talk about him," Jansen says, making sure it's clear he understands the gravity of what he's about to say. "But honestly, I've been learning from watching Mariano's tape."
Two lockers down, third baseman Juan Uribe can't help but intervene.
"So you want to be like Mariano?" Uribe jokes, despite Jansen's best efforts to contextualize the statement.
At this point, it doesn't matter what Jansen says. He could point out that, like Rivera, his cut fastball has become among the most devastating pitches in all of baseball. Opponents are hitting just .184 against Jansen's cutter this season, third best among all relievers in baseball and comparable to a typical Rivera season (2010), when opponents hit just .174 against his cutter.
He could also mention that he recently retired 27 straight batters -- a rare, hidden perfect game -- during a sizzling stretch in late July and early August. Or he could just shrug and joke that Uribe "is 0-for-1 against me, matter of fact."
Jansen opts for the latter.
He has been a pitcher since only 2009, when the Dodgers convinced him he just wasn't a good enough hitter to make it to the big leagues as a catcher, but it'd be a shame to let that golden right arm top out behind the plate in the low minor leagues.
He has been the Dodgers' closer for only a few months now, taking over after Brandon League scuffled.
But if there's one thing he has learned during his metamorphosis, it's that talk is cheap. Results matter, and he got Uribe out.
"I always wanted to be a closer," Jansen explains. "I don't need to talk about it. The way I perform out there, that's how I show people I really want it. I don't want to ask for it, I just want to show it by how I perform."
Before Uribe jumped into the conversation, Jansen was also about to explain that he was watching tapes of Rivera not to try to decipher how he mastered the cutter -- which, lore has it, came to him as naturally as it does to Jansen -- but to see how he carries himself during a game. How he reacts to situations, good and bad. If his approach ever changes, or how he gets through a save when his stuff isn't crisp.
"One thing I keeping coming back to with Mariano is, 'He blew up in the World Series. He blew up in the ALCS, and he's still the greatest of all time. He's tough. He's so tough. That's why he's so good,'" Jansen says.
It's a mentality all closers must have. Something that can be learned, but only if the hard-wiring is there to begin with. Jansen has got it, but he's playing catch up.
Three years ago he was still getting used to the idea of calling himself a pitcher. His stuff was electric, but he was just beginning to harness his power, let alone master the mysteries of pitching.
The next two seasons, he was just as good on the field -- a 2.83 ERA and staggering ratio of 16.1 strikeouts per nine innings in 2011 (second best of all time), and 2.35 ERA and 13.71 K's/9 IP ratio in 2012 -- but a scary heart condition hung over him and his development, making it difficult to develop any consistency in his routine.
This year, after offseason surgery to correct the condition, he's finally been able to work on his craft with the type of consistency and focus it takes to extract greatness from the raw, natural ability he has been given.
"I totally have a different mindset than before," Jansen says. "Three years ago, even last year, I was just trying to get my feet wet in the closer role. I didn't really have the identity or know what to do. But I've learned more about it, about the mindset, it's starting to click."
There's a difference in closing games and being a closer. One is an action, the other is a way of being. One is a title, the other is an identity.
It's that leap Jansen is working on.
"Hardly anybody just comes in and takes over that role," Dodgers pitching coach Rick Honeycutt said. "That inning is a different inning. Getting those last three outs of a game. I didn't have to do it much in my career, but in talking with Eck [Dennis Eckersley, Honeycutt's teammate in Oakland] over the years, you can't get ahead of yourself. You can't be at that third hitter before you get that first hitter.
"I think that's where [Jansen's] at now. He's simplified things -- attack, put this guy away in three or four pitches, move on to the next guy and then the thing's over with. Don't get ahead of yourself. It's easy to talk about, but you have to experience it.
"He'd been a part of the game, but he hadn't pitched. The beauty of it now is that he's taking on that role, he talks to people about it, and he's embraced it."
The turning point this season, both Honeycutt and Jansen said, came after a shaky 28-pitch save in Toronto on July 23.
"[Dodgers manager Don Mattingly] challenged him in Toronto, after that 28-pitch save," Honeycutt said. "He was like, 'Kenley, if you're going to use that many pitches, it affects the rest of the week.'
"He's just been so efficient since then."
Jansen had a different explanation.
"The thing is, you're not going to be great all the time out there. You're not going to have your stuff. But you have to be mentally tough even when you don't," Jansen said. "You have to figure out how you're going to get out of that situation even when you don't have your best stuff. The Toronto game, I could tell from the first throw warming up in the bullpen that I didn't have my stuff. So I just said to myself, 'I've really got to battle,' and I did.
"That pumps your confidence because you battled and you won, even without your best stuff. That got me going, competing like that. Nobody's going to be perfect and nobody's going to have a zero ERA. It's about who is going to be toughest out there."
If you know Jansen at all off the field, it's funny to hear this competitive side of his come out. Away from the game, he's thoughtful, polite and easy going. He speaks perfect English, having been schooled in four languages -- English, Spanish, Dutch and Papiamento, the native tongue of his island homeland, Curacao.
During the offseason, Jansen's often at Lakers or Clippers games, or watching his favorite all-time player Shaquille O'Neal on TNT. Blake Griffin and Kobe Bryant are his favorite current players.
He's also home in Curacao for a month or two each winter, developing his foundation, KJ74, which works to create opportunities for children to participate in sports.
Before most games, he's usually at his locker chatting with teammates or reporters. He's friendly, not intimidating.
When you have a devastating pitch like Jansen's cutter though, what more really needs to be said?