As competition drives teams to look for talent anywhere they can find it, clubs are employing more information than ever, both scouting and statistical, while getting increasingly better at knowing how to utilize it. Even with all of that competition, with a little information and a little luck, teams can acquire a player ready to make an immediate major league impact at virtually no cost. As examples such as Dan Uggla, Josh Hamilton, and Joakim Soria reflect, All-Stars can be found in the most unlikely of places, provided one knows where to look — and which rule to follow.

Each December at baseball’s winter meetings, the Rule 5 draft allows teams to acquire eligible players left off of 40-man rosters after three or more professional seasons, provided the drafted player is kept on the 25-man roster of his new team for a full season. Selections cost the drafting team a mere $50,000. Clubs rarely leave a good prospect unprotected, and while there have been exceptions — notably in 1999, when Johan Santana was plucked by the Twins from the Astros — usually the players taken aren’t productive, and are frequently offered back to their original team for half the original cost at the end of spring training.

That’s been changing of late. In the 2005 and 2006 drafts, three players were taken who have not just established themselves, but have emerged as stars. Through Wednesday’s games, Rangers outfielder Hamilton and Marlins second baseman Uggla led the American League and National League, respectively, in extra-base hits, while Royals pitcher Soria has become one of the game’s dominant relievers. Hamilton’s story is among the most amazing in the game; picked first overall in the 1999 amateur draft by Tampa Bay, he fought through a cocaine addiction to make it to the majors after three years away from professional baseball at any level.

Hamilton’s story might have its statistical match in Uggla’s unexpected rise to the ranks of the game’s top sluggers. He was drafted by the Marlins from the Diamondbacks organization in 2005 after his age-25 season in Double-A, a year in which he hit 21 home runs with an .880 OPS. Uggla smashed 27 homers and batted .282 AVG/.339 OBA/.480 SLG as a major league rookie, becoming the first Rule 5 pick to be named an All-Star in his inaugural season. In 2007, Uggla’s batting average slipped to .245, but he displayed even more power, socking 31 homers, three triples, and 49 doubles, one off of the league lead. Uggla’s 83 extra-base hits in 2007 ranked sixth all-time among second basemen, behind only Rogers Hornsby, Alfonso Soriano, and Charlie Gehringer: two Hall of Famers, and one who might well reach Cooperstown. Research conducted by Rany Jazayerli of Baseball Prospectus showed that Uggla and Marlins shortstop Hanley Ramirez combined for more extra-base hits than any other double-play pairing in major league history; their total of 166 extra-base hits narrowly eclipsed another 2007 NL East tandem, MVP shortstop Jimmy Rollins and second baseman Chase Utley of the Phillies, who together had 163.

This season, Uggla has only gotten better. Through Wednesday’s action, he was second in the major leagues in home runs, with 16, and tied for first in doubles, with 19. His hot stretch has him on pace to blow by Hornsby’s single-season record for extra-base hits (102) by a middle infielder, set in 1922. The way Uggla is going, he might even have a slim shot at joining the club operated exclusively by Albert Belle — the only player to hit 50 homers and 50 doubles in the same season.

It is highly unlikely that Uggla will keep ripping the ball all over the yard like a 21st-century Hornsby: His most optimistic forecast from PECOTA, BP’s prediction system, pegs him for 79 extra-base hits this season. Still, even factoring in a drop-off, Uggla has already become one of the greatest offensive successes of the Rule 5 draft, joining Hall of Famer Roberto Clemente (taken by the Pirates from the Dodgers in 1954), Darrell Evans (by the Braves from the Athletics in 1968), and George Bell (by the Blue Jays from the Phillies in 1980). There is also Hamilton, who besides leading the AL in extra-base hits (31), is also the major league RBI leader (58) in his first full season.

A year after Uggla’s selection, Hamilton was selected by the Cubs with the third pick of the 2006 Rule 5 draft; they immediately sold him to the Reds. One pick before Hamilton’s selection, though, the Royals selected Soria from the Padres. Soria had spent most of the 2006 season in the Mexican League before being signed by San Diego, and only a year later was closing games for a major league team. Soria struck out 9.8 batters per nine innings (K/9) and allowed less than a base runner per inning, producing the ninth-best K/9 and with a 0.94 WHIP, the seventh-best WHIP of any rookie reliever in history to throw at least 60 innings.

Like Uggla and Hamilton, Soria has improved on an already impressive start to his career, with just two runs allowed in 21 appearances and a 25/5 K/BB ratio. While it would be nearly impossible to overtake Santana as the best pitcher picked via Rule 5 in the modern era, Soria is on his way toward challenging Willie Hernandez, the relief ace on the 1984 world champion Tigers who won the AL MVP and Cy Young awards, as the best fireman in the draft’s history.

The 2006 draft might yield at least one more standout: catcher Jesus Flores, who was snatched away from the Mets by the Nationals after he led the High-A Florida State League with 21 homers as a 21-year-old. Flores took his lumps last year upon jumping up three levels to join Washington. But PECOTA is extremely bullish on his offensive potential, and Baseball Prospectus 2008 predicted that an All-Star Game could be in his future. With both of the Nationals’ regular catchers hurt, Flores has seized upon that promise, putting up a 1.010 OPS in 69 plate appearances. If Flores does eventually play in the Midsummer Classic, he would join Hamilton and Soria — both near-certainties to make the All-Star team this season — as the third player to earn that distinction from among the 19 players chosen two winters ago.

Mr. Peiffer is a writer for Baseball Prospectus. For more state-of-the-art commentary, visit baseballprospectus.com.