But early this season, there are some who have found their way to The Show via the roads not often traveled, and they are looking quite valuable to their clubs at the moment.
Take Tom Wilhelmsen, the tall, hard-throwing right-hander for the Seattle Mariners. In 2002, he was selected by the Milwaukee Brewers in the seventh round of the First-Year Player Draft. By 2004, he was done with baseball, having been suspended twice by the Brewers for drug use. He poured drinks for a living at The Hut, a bar in his hometown of Tucson, Ariz., and pitched in a few games for an independent team there in 2009. The Mariners signed him, because they saw a guy with a great arm and a lot more maturity.
On April 3, 2011, he was in the Mariners bullpen. And then, last July, he became their closer.
"Everyone learns and gets it at a different time in their life," Wilhelmsen said. "Was mine later than others? I don't know. I know my life, and that's what I go by."
This year, his life has been going quite well. Now 29, he has ridden his mid- to high-90s fastball and 12-to-6 curve to six saves in six opportunities and a 1.00 ERA entering Tuesday's game in Houston.
"It's quite a story," Mariners manager Eric Wedge said. "You wouldn't know it by the way he carries himself and the stuff you see. You have to like the way he carries himself out there, just his presence."
Evan Gattis has always had presence. That isn't very hard when you're 6-foot-4 and 230 pounds. But a Major Leaguer? That didn't seem very likely for a long while.
Gattis, 26, was a 19-year-old prospect out of Bishop Lynch High School in Dallas, but was lost in depression and alcohol and marijuana use. He didn't feel like playing baseball at Texas A&M. He didn't feel like playing baseball at all, in fact.
So he went to rehab and then took odd jobs. He was a janitor and a cook. He operated a ski lift. He cleaned up after people at a hostel. But baseball never left his mind, and he went back to the game, playing at the University of Texas Permian Basin and being drafted by the Braves in the 23rd round in 2010.
Now he's not only in the Major Leagues, having made Atlanta's Opening Day roster, but he homered off Roy Halladay in his second big-league at-bat, and through Monday, Gattis has earned everyday playing time. Through his first 52 big-league at-bats, he had five homers and 12 RBIs and was slugging .596.
And how about Scott Rice? Two years ago, the lefty reliever was pitching independent ball for the York (Pa.) Revolution at the age of 29. He was in his 12th Minor League season. Every time he had gotten close to the Majors, an injury or a last-minute decision had derailed him.
But not this year. Rice hooked on with the Mets, did well in Spring Training and made the team. Entering Tuesday, he had appeared in 10 games and compiled a 1-0 record and 1.00 ERA.
"It's been a journey, man," Rice said. "I've been through a lot of adversity. I've been through a lot of things that don't happen in a normal career. I just keep pushing on."
The same can be said for all these players, who have as much persistence as they do baseball skills.
Daniel Nava was an undrafted outfielder signed by the Red Sox out of an independent league in 2008. He was the classic organizational guy, not expected to do much beyond helping out the Minor League system. And then he hit and hit some more, and when he was called up to the Majors in 2010, he didn't waste time making his presence known. He hit the first pitch of his big league career for a grand slam.
Three years later, he's a fixture in Boston. Through 15 games entering Tuesday, he had a slash line of .320/.429/.600 with four homers and 14 RBIs. And the flair for the dramatic hasn't eluded him. Last Saturday, in the first game at Fenway Park following the Boston Marathon bombing and subsequent manhunt for the suspects, Nava blasted a three-run home run that ended up being the game-winner.
Meanwhile, in Philadelphia, another player who seemingly came out of nowhere is making his mark.
Erik Kratz is 32 years old and had toiled in the Minors for nine seasons when he got a phone call during the Triple-A All-Star Game in Allentown, Pa., in 2010.
It was the Pittsburgh Pirates, his parent club at the time, telling him he had finally made it to the Majors, and now, in 2013, he's the Phillies' backup catcher. Last year with Philadelphia, he hit nine homers and drove in 26 runs with a .809 on-base-plus-slugging percentage in 141 at-bats. This season, he's already got two homers and seven RBIs.
Kratz, like Wilhelmsen, Gattis, Rice and Nava and many more to come in the future of this great and crazy game, has overcome doubt and the disappointment of rejection to enjoy this exalted stage playing the game he loves. Sometimes, it really does pay off.
"You sit there and you put all the work in and sometimes you question why," Kratz said the day he was called up.
"You put the work in and at the end of the day, if you don't measure up or you fall short of where you want to get to, you've put in what you could. That's where I was in my career. That was pretty much all that was pushing me."