Sports Illustrated have this list in the current issue,they didn't say how they came up with the list but it's interesting reading, I don't think it's in numerical order either.
Signed at 16 for a $710,000 bonus, the Venezuelan has drawn comparisons to Dwight Gooden after just four major league starts. Hernandez, who is the first 19-year-old to debut as a starter since Todd Van Poppel (1991) and Gooden ('84), has struck out 30 batters and walked three in winning two of his first three decisions.
After a stellar career at USC, Prior needed only nine minor-league starts to reach the majors at 21. He won six of his 19 starts as a rookie before going 18-6 with a 2.43 ERA and leading the Cubs to the NL Central title in 2003
St. Louis Cardinals
The young lefty breezed through the minors, garnering Minor League Player of the Year awards from USA Today and Baseball America in 1999. But after a promising rookie season during which he won 11 games for the Cardinals as a 21-year-old, he lost his control in a surprise first-round playoff start, throwing five wild pitches in an inning, won only two games over the next four seasons and gave up pitching to become a hitter.
The young Texan announced his arrival with a record-tying, 20-strikeout performance against the Astros on May 6, 1998, at the age of 20. Wood went on to win NL Rookie of the Year honors, ranking third in the league in strikeouts while going 13-6 with a 3.40 ERA, but missed all of 1999 with an elbow injury
The Tribe rode its 21-year-old rookie all the way to Game 7 of the World Series. Wright posted an 8-3 record during the regular season and went 4-0 in the playoffs, including the deciding Game 5 victory against the Yankees in the first round. Injuries derailed his career, though; he's been a journeyman the past few seasons.
Kansas City Royals
After winning 10 games as a 20-year-old rookie in 1984, Saberhagen led the Royals to their only championship, winning the first of his two Cy Young awards and World Series MVP honors as well. The control artist finished with a respectable 167-117 record in 16 seasons with the Royals, Mets, Rockies and Red Sox.
New York Mets
The Doctor was in. In 1984, NL Rookie of the Year Gooden became the first teen-ager to win at least 17 games since Baltimore's Wally Bunker went 19-5 in '64. One year later, Gooden would tear through the league, going 24-4 with a 1.53 ERA and winning the Cy Young award. However, off-the-field problems contributed to Doc Gooden falling short of his Hall of Fame potential.
Los Angeles Dodgers
"Fernandomania" took off in 1981 as the 20-year-old screwballer won his first eight starts and won the NL Cy Young and Rookie of the Year awards while sparking the club to its first World Series title since 1965. Valenzuela became a workhorse for the Dodgers throughout the 1980s, surpassing the 200-innings mark seven times.
Just one year after being drafted, the 19-year-old curveball artist came up to the majors and helped the Twins claim their second consecutive AL West crown by going 10-9 with a 3.18 ERA. Twenty-two years later, Blyleven retired with 287 career victories and the fifth-most strikeouts (3,701) in history.
At 22, Blue had a season for the ages in 1971 as he won 24 games and took home the AL Cy Young and MVP awards for the AL West champion A's. Two years later, Blue would win 20 games again as the A's claimed their second of three consecutive World Series titles. Blue's final record: 209-161, 3.27 ERA, six All-Star Games
The future Hall of Famer became a full-time starter as a 20-year-old in 1966 and led the world champion Orioles in victories (15) and innings pitched (208 1/3). On Oct. 6, 1966, he blanked the Dodgers in Game 2 to become the youngest pitcher to throw a World Series shutout.
He posted his first big season at 21 in 1957: 17-9, 2.69 ERA, 221 IP. The future Hall of Famer won the NL strikeout crowns in 1959 and '60 and played on three of the Dodgers' world championship teams. In 1968, he tossed a then-record 58 2/3 consecutive scoreless innings in 1968.
"Rapid Robert" won the first of his seven AL strikeout crowns as a 19-year-old in 1938. He won 17 games that year and would win 24, 27 and 25 games during the next three seasons of what would become a Hall of Fame career
Boston Red Sox
Before he became The Sultan of Swat, the Babe was the ace lefty of the Red Sox. He went 18-8 with a 2.44 ERA in 1915 at the age of 20 as Boston won the first of its three World Series with Ruth.
New York Giants
The original phenom established himself early on as a major force, winning 20 games as a 20-year-old in 1901. His 373 career wins rank third on the all-time list behind only Cy Young (511) and Walter Johnson (417).