His numbers were solid. His reputation was imposing.
He has since learned his lesson.
The Dodgers believe that they have, as Manager Don Mattingly put it, "one of the top guys in the show," that Jansen is "one of the best closers out there." Few in baseball would disagree, and the statistics support his case.
Yet Jansen has never made an All-Star team. Each season, Jansen said, he has gotten his hopes up and ended up disappointed. So this year, he is not expecting anything.
"I think I have a shot this year, but who knows?" Jansen said. "I just don't want to get surprised."
Had Jansen pitched more innings this season, he'd likely be a lock to make the team, whose starters will be announced Sunday and reserves Monday. But he missed the first month and a half after undergoing off-season foot surgery.
He still has 13 saves in 14 opportunities, and he earned a win after that one blown save. His earned-run average is 1.53 and opponents are batting just .133 against him. On Tuesday, in his 17th appearance, he finally yielded his first walk of the season.
"I don't know," he said. "It's just the way the way the All-Star is sometimes. I don't know. It's a little overrated, I feel like. Because if you look at people's numbers, right, certain people aren't going to get in."
And certain people, he said, are victims of the limited number of roster spots and the inclusion of relievers from teams without another All-Star. This year, there's a good chance that will leave Jansen off the team again.
Last year, both leagues ultimately named six relievers to the team, including substitutes for injured players. This year, the St. Louis Cardinals' Trevor Rosenthal is a near lock, as is New York Mets closer Jeurys Familia.
The Milwaukee Brewers' Francisco Rodriguez, Arizona Diamondbacks' Brad Ziegler and the Miami Marlins' A.J. Ramos all have better earned-run averages, and all pitch on teams with limited save opportunities.
Mattingly said the selections could come down to philosophy. Do you reward the best players, or the players who've had the best year?
"Sometimes it's the amount of saves or the body of work or just how good he is," Mattingly said. "So if he's just going to say how good he is, is he one of the best? Then I think he should be on the All-Star team."
Jansen could end up battling for a spot against Aroldis Chapman of the Cincinnati Reds, who are hosting the All-Star game. Chapman has made the All-Star team the past three years, and his career numbers are strikingly similar to Jansen's.
Chapman has 10 more saves but Jansen has a slightly better ERA. Chapman owns a better opponents' batting average, but Jansen gives up fewer walks and hits per inning. Chapman, who throws harder than perhaps anyone in the league, has 12 more strikeouts.
Jansen knows the similarities.
"If you compare us, how good of a closer we are, we'd be the same type," Jansen said. "That's what I'm saying. He's one of the top closers in the game, but the only thing is he's got an All-Star appearance. I don't."
Jansen said he wasn't diminishing what Chapman has done. The point is, he said, "It just doesn't make any sense sometimes."