Age 22: Bruce Ruffin (1986)
Ruffin was drafted by the Phillies out of the University of Texas at Austin in the second round in 1985. After going 13-9 with an ERA around three in 30 minor league starts, the Phillies called up Ruffin after the release of Steve Carlton in June 1986.
The 22-year old made his Major League debut against the Cardinals on June 28, allowing three earned runs on seven hits with five strikeouts over 6 1/3 innings. Ruffin earned his first Major League win against the Reds five days later followed by a two-hit shutout of the Braves.
After losing three of his next four decisions, Ruffin won six of his last seven decisions and finished the rookie campaign with a 9-4 record and 2.46 ERA in 146 1/3 innings. Ruffin won 11 the following season, but his ERA soared to 4.45. He could never again approach those rookie numbers, finishing six years in Philadelphia with a 42-58 record and 4.18 ERA.
Ruffin went on to pitch six more seasons in the Major Leagues, one with the Brewers and five with the Rockies before retiring with a 60-82 record, 63 saves and a 4.19 ERA.
Age 23: Cole Hamels (2007)
Hamels dominated in 18 minor league games as a 19-year old in 2003, posting a slim 1.34 ERA in 101 innings. After injuries limited him to 10 games in 2004 and 2005 combined, Hamels got his shot with the Phillies in 2006. In 23 starts, he went 9-8 with a 4.32 ERA, striking out 145 in 132 1/3 innings.
The 2007 season, Hamels showed he could become one of the top pitchers in the National League. Making his first All-Star appearance, the 23-year old went 15-5 with a 3.39 ERA in 28 starts, striking out 177 with 43 walks in 183 1/3 innings. Hamels also finished sixth in the Cy Young Award vote, the second-highest of his career.
Hamels was dominant in the 2008 postseason after 14 regular-season wins. His overall best season with the Phillies was in 2012, posting a 17-9 mark with an ERA of 3.05 with 216 strikeouts. Hamels capped his Phillies career with a no-hitter against the Cubs in July of 2015.
Since his departure from Philadelphia, Hamels had an All-Star appearance with the Rangers in 2016 as well as a season and a half with the Cubs. Now with the Braves, Hamels has a career record of 163-121 with 2558 strikeouts and a 3.42 ERA.