NOTE: All pitchers on this list will be 25 or younger as of June 30, 2008.<br><br>Even with just 17 games of big league experience, he's earned the third slot in the Rockies' starting rotation, and with better location on his 100-mph fastball, Colorado could have an ace in the making.
2 of 20Lisa Blumenfeld/Getty Images
Tom Gorzelanny, 25, Pirates
One of the few bright spots in the Pirates franchise, Gorzelanny went 14-10 with a 3.88 ERA last season and surpassed the 200 innings mark for the first time in his career.
3 of 20Brad Mangin/SI
Matt Cain, 23, Giants
In only his second full season in the big leagues, Cain reached the 200 innings mark in 2007. A lack of run support saddled him with a 7-16 record, but his ERA was an excellent 3.65 and he struck out 163 batters.
4 of 20Brad Mangin/SI
Yovani Gallardo, 22, Brewers
The Brewers came to rely on the rookie right-hander last year after his mid-June call-up. In 17 starts, he allowed more than three runs only four times in going 9-5 with a 3.67 ERA.
5 of 20Chuck Solomon/SI
Matt Garza, 23, Rays
Garza was supposed to show his skills in the 2007 Futures All-Star game, but, instead, headed to the majors. Though he only played half the season, he still managed to make 15 starts and post a 3.69 ERA.
6 of 20Phil Ellsworth/SI
Chad Billingsley, 23, Dodgers
The strapping right-hander came into his own after joining the rotation in late June. Billingsley went 8-5 with a 3.38 ERA and 101 strikeouts in 112 innings as a starter from that point on.
7 of 20Damian Strohmeyer/SI
Clay Buchholz, 23, Red Sox
The top prospect for the world champs has only pitched in four games for the Sox, but managed to throw a no-hitter in one of them. But over 22.2 innings, he owns 22 strikeouts.
8 of 20David Bergman/SI
Jeremy Bonderman, 25, Tigers
Lost 19 games as a 20-year-old rookie in 2003, but has posted four straight 10-win seasons since and had 145 strikeouts in 174.1 innings in 2007.
9 of 20Chuck Solomon/SI
Homer Bailey, 22, Reds
The seventh-overall pick in the 2004 draft is intimidating just to look at: 6-foot-4, 205 pounds. Add his 97-mph fastball and a diverse repertoire of pitches, and it's clear Bailey gives the Reds their best young pitching prospect in years.
10 of 20Damian Strohmeyer/SI
Phil Hughes, 21, Yankees
If you thought Bailey or Bonderman was big, try 6-foot-5, 200-pound Hughes. The youngest Yankee pitcher boasted 5-3 record before it was cut short by a strained hamstring last year.
11 of 20Al Tielemans/SI
Jon Lester, 24, Red Sox
Most of the attention on him last year focused on his return from cancer, but his pitching deserved notice, too. He won the World-Series clincher (he pitched 5 ⅔ shutout innings in Game 4) and totaled 50 strikeouts in 63 innings on the year.
12 of 20Brad Mangin/SI
Tim Lincecum, 24, Giants
"Seabiscuit" is short in stature but not on talent. The homegrown product struck out 150 batters in 146 ⅔ innings last season while posting a 7-5 record and 4.00 ERA.
13 of 20John W. McDonough/SI
Jered Weaver, 25, Angels
The younger brother of pitcher Jeff Weaver fought through an arm injury last season to post decent numbers: 13-7, 3.91 ERA. This was after a breakout rookie year in which he went 11-2.
14 of 20Darren Carroll/SI
Joba Chamberlain, 22, Yankees
Bugs had more luck getting to Joba than big league hitters during his phenomenal rookie season in 2006 when he struck out 34 in just 24 innings and allowed only two runs.
15 of 20Al Tielemans/SI
Francisco Liriano, 22, Twins
A fascinating debut in 2006 -- 13-5, 2.74 ERA -- earned him the nickname "Franchise" but he hasn't pitched in a big league game in over a year after undergoing Tommy John surgery.
16 of 20Kohjiro Kinno/SI
Felix Hernandez, 22, Mariners
The King battled lofty expectations and a brief arm injury to make 30 starts for the second consecutive season. Though his numbers weren't spectacular, he did win 14 games with a 3.92 ERA for a Mariners club that overachieved to win 88 games.
17 of 20AP
Scott Kazmir, 24, Rays
Kazmir has the makings of a big-time winner. Last season he went 13-9 with a 3.48 ERA and 239 strikeouts for a Rays team that won only 66 games. With more defensive support behind him he could blossom into a 20-game winner in 2008.
18 of 20David E. Klutho/SI
Cole Hamels, 24, Phillies
The fireballing southpaw emerged as the staff ace with 15 wins and a 3.39 ERA last season as the Phillies came back to steal the NL East title from the Mets.
19 of 20
Fausto Carmona, 24, Indians
After failing miserably as a reliever in 2006, Carmona came to life when given a spot in the rotation last season. He helped carry the Indians to within one win of the American League pennant, winning 19 games and placing fourth in Cy Young voting.
20 of 20Bob Rosato/SI
Justin Verlander, 25, Tigers
His no hitter against Milwaukee last June was certainly memorable, but his 3.66 ERA and 18-6 record to become the first Tiger to lead the American league in winning percentage last year established him as one of the game's best.
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