Players eligible for the Rule 5 Draft are those who signed with a team when they were 19 or older and have played professionally for four years, and those who signed at 18 and have played for five years, and in either case are not on a Major League team's 40-man roster. Such players can be plucked from their original team in the Major League phase of the Draft and placed on the new team's 25-man roster for a fee of $50,000.
There are two other phases, a Triple-A Draft and a Double-A Draft. The rules are about the same, but the fees are less.
Unlike a trade, a Rule 5 Draft selection provides a guaranteed opportunity at Spring Training as a team that took a player in the Major League phase must have him on its 25-man Opening Day roster and keep him on it for the entire season or offer the player back to his original team. If the original team declines the offer, the player must be exposed to waivers.
The Rule 5 Draft concept is unique to Major League Baseball in that it allows a team to snag an underrated player from another organization and give him a shot to make the Majors.
Opportunity is thrust upon Minor Leaguers who instantly jump from depth prospect to a Major League roster spot when their name is called during the Winter Meetings in December.
"It's the best thing ever," said Mariners pitcher Lucas Luetge, taken from the Brewers in 2011. "I went from Double-A to the big leagues in the matter of an offseason."
It was a surprise in more ways than one for the reliever, who went on to pitch in 63 games with a 3.98 ERA out of the bullpen the following season.
"I didn't know what the Rule 5 Draft was before it happened," Luetge said. "I got the call that said, 'You got drafted,' and I had to look it up on the Internet to see what it meant."
Nine players were selected in the Major League phase of the most recent Rule 5 Draft. One of them was pitcher Seth Rosin, who was selected from the Phillies by the Mets and was subsequently traded to the Dodgers.
"Having a shot is eye-opening," Rosin said. "It's a lot of fun knowing that I can compete for a [Major League roster] spot this year, unlike the last time I was at a Major League camp, when I knew that I had no chance."
Like Rosin, selections can be traded, but the rules still apply.
More than 200 players have been selected in the past 15 years, including All-Stars Johan Santana (1999), Jose Bautista (2003) and Josh Hamilton ('06). Infielder Dan Uggla had success right away, becoming the first player to make an All-Star Game in his first season after being selected by the Marlins from the D-backs in 2005.
For all the success stories, players still face an uphill battle to earn a full-time roster spot, as many of them do not stick with their new clubs.
It is a big transition going from the Minors to the Majors, and the first battle is a mental one.
"You've got to be able to keep your emotions in check, because you're starting to see the big names you've watched on TV your whole life," Luetge said.
"At my first stretch, I look over and Ichiro [Suzuki] and Felix [Hernandez] are over there, and it's kind of surreal. All I knew about these guys is what I saw on TV; now I'm stretching with them," Luetge said.
Excitement and nerves are always a factor when joining a new team.
"I was a little timid coming [to the Rockies], because I didn't know anybody," said pitcher Tommy Kahnle, taken from the Yankees in December. "It's going to be a little strange, but so far it's been cool."
In the end, the Rule 5 Draft is all about opportunity. One team thinks enough of a young player to bring him into its clubhouse and see if he can make the team.
"It's kind of an honor," Kahnle said. "It's cool [the Rockies] wanted me. If I pitch well, maybe they'll keep me."