Some relievers thrive when they move into the huge ninth-inning spotlight and some fizzle. And others turn into one-year wonders.
They can be a Jimmy Fallon, earning raves, a Conan O'Brien deflecting razzes, or one of those single-season phenoms that's increasingly common, a bullpen Halley's Comet that gets all the attention one summer and disappears the next.
After a half-decade as Mariano Rivera's understudy in the New York Yankees' bullpen, David Robertson feels ready for his move to the big time.
"I'm hoping it's more fun," Robertson said. "You get to high-five with everybody at the end of the game instead of just running in the dugout and going, "OK, Mo's coming in. I'm going to go get undressed and get ready to high-five him when he comes in the clubhouse.'"
Top closers are baseball's rock stars - tied to their entrance music and their oversized persona, whether of chaos or cool. It's hard to think of Rivera without Metallica's "Enter Sandman" or Trevor Hoffman divested of AC/DC's "Hells Bells."
But for every success there are multiple failures, especially these days when the managers and front-office executives feel intense pressure for their teams to produce right from the season's start and every single night.
Hence, the reliever who goes from obscurity to supremacy and back.
"In the case of relievers, if you check the history it's kind of a natural wave of things," Baltimore Orioles pitching coach Dave Wallace said. "A lot of guys have a real good year, or maybe two good years, and then maybe hit a bump in the road for a year or two. That's what makes Trevor Hoffman, Mariano, those type of guys special because they've done it over a long period of time."
From 1969, when the save first became a statistic, until 2003 there was not a single occurrence of a pitcher who had exactly one 30-save season and no other, according to STATS.
Shawn Chacon became the first. An All-Star starter for Colorado in 2003, he was converted to closer the following year and had 35 saves - but also blew nine and became the first player in major-league history with 30 saves and an ERA over 7.00.
Restored to the rotation for 2005, he struggled and was dealt to the Yankees. Chacon started for most of the remainder of his career, which ended in 2008, and got just one more save.
Toronto's Miguel Batista (2005) was the next with a one-time-only 30-save season, followed by Texas' Akinori Otsuka (2006) and Toronto's Jeremy Accardo (2007).
In the last three years, seven pitchers have reached 30 saves for the first time and it remains to be seen whether they will do it again: Sergio Santos (2011), Drew Storen (2011), Jordan Walden (2011), Tyler Clippard (2012), Jason Motte (2012), Jason Grilli (2013) and Edward Mujica (2013).
"Some guys are built for it and some guys aren't," Miami Marlins manager Mike Redmond said. "If you can throw strikes and get guys out and save games you are going to have that job forever, but as soon as you don't they find somebody else who does, right? It's just the nature of the beast."
Koji Uehara had 13 saves for Baltimore in 2011, then had one save in each of the following two seasons. After opening last season in a setup role for the Red Sox, he got the big job when Joel Hanrahan tore an elbow ligament and Andrew Bailey struggled and needed shoulder surgery. By October, the 34-year-old Uehara was dominant, striking out St. Louis' Matt Carpenter to finish Boston's first World Series clincher at home since Babe Ruth's team back in 1918.
Tampa Bay manager Joe Maddon likened Uehara to Fernando Rodney, who saved 37 games for Detroit in 2009, served mostly as a setup man during two seasons with the Los Angeles Angels, then emerged as a top closer for the Rays before signing with Seattle. Rodney succeeded when he commanded his changeup and Uehara excelled when he mastered his splitter.
Rivera became baseball's greatest closer because of his cutter, which shattered bats of hundreds of left-handed hitters.
"I have to believe the common thread is a great other pitch, which more than likely is going to be a changeup or a split," Maddon said. "The way that Rivera did it consistently for so many years, it seems it's difficult today to get relief pitchers to be consistent for that many consecutive years."
Rodney's changeup fell into place because of a change in his mechanics.
"A pitcher always lifts his foot. So I stayed in my slide step and got the same velocity, everything the same," he said. "I pitched really well in the Dominican Winter League and I came to spring training continuing to work. And I got a lot of positive results."
With Rivera's retirement, 39-year-old Joe Nathan becomes the active saves leader with 341. He's preparing for his first season with the Tigers, a "Guys and Dolls" pairing of Nathan-Detroit.
Robertson, who turns 29 next month, has all of eight career saves to his credit. When Derek Jeter retires at the end of the season, Robertson will become the longest-tenured Yankees player if he remains with New York, one day more than outfielder Brett Gardner.
Friends have texted him congratulations on taking over Rivera's role. He keeps saying it's no big deal, he's approaching the ninth in the same manner he pitches the eighth.
"You blow a game, well, you're going to hear about it. No one wants to lose games," he said. "Believe me, I've done it in the eighth inning. I've lost games, a bunch of games. It's a little more pressure on you in the ninth, but I still think it's still a job. You're trying to do the same thing. You're trying to get three outs as quickly as possible. You want to minimize damage and make quality pitches and finish the game. End it."