Many of MLB's best active players happen to be under the age of 25. Early in the 2013 season, it's clear that Mike Trout, Bryce Harper, Craig Kimbrel and others on this exclusive team have many years of stardom ahead of them.
Sample sizes for all the top candidates are small, so potential was weighed nearly as heavily as past production when determining who to include.
Players needed to have major league experience at a position to be considered for it. Starlin Castro, for example, has only been used at shortstop and therefore, could not be shifted to second or third base.
If there's a takeaway from this article, it is that we're living in a golden age of baseball. Young athletes now enjoy initial successes because they enter the professional ranks with more knowledge and discipline than their predecessors.
*Ages current as of April 8, 2013.
**Career WAR is averaged from Baseball-Reference.com and FanGraphs.
Clayton Kershaw (Los Angeles Dodgers)
The southpaw has been the National League's top starting pitcher since 2011.
Aside from an outstanding strikeout-to-walk ratio, Kershaw provides lengthy outings and occasional offensive contributions. Fans saw the whole package from him during a historic Opening Day performance (via Jay Jaffe, SI.com).
Justin Upton (Atlanta Braves)
Before those Bryce Harper and Mike Trout people came along, Upton was hyped as baseball's most talented position player. The outfielder has averages of 23 home runs and 19 stolen bases over the past four full seasons.
Entering April 8, he leads the National League with five long balls.
Aroldis Chapman (Cincinnati Reds)
It would have been intriguing to see the Cuban Missile stretched out, but at least as a closer, he can dial up his fastball into triple digits.
Chapman made the jump from adequacy to excellence in 2012 due to improved command. It's safe to assume that he'll be an NL All-Star once again.
Mat Latos (Cincinnati Reds)
One of the truly underrated pitchers in baseball, Latos annually increases his workload. He now has finished three consecutive seasons with a sub-3.50 earned run average.
Aside from Gio Gonzalez and Zack Greinke, there might not be a better No. 2 starter in the majors.
We initially whittled down the list to 30 young players before selecting half for the roster.
These 15 were seriously considered, but ultimately excluded:
Andrelton Simmons (Atlanta Braves), Chris Tillman (Baltimore Orioles), Will Middlebrooks (Boston Red Sox), Starlin Castro and Anthony Rizzo (Chicago Cubs), Dayan Viciedo (Chicago White Sox), Wilin Rosario (Colorado Rockies), Kelvin Herrera and Eric Hosmer (Kansas City Royals), Jarrod Parker and Dan Straily (Oakland Athletics), Ben Revere (Philadelphia Phillies), Yasmani Grandal (San Diego Padres), Neftali Feliz (Texas Rangers) and Brett Lawrie (Toronto Blue Jays).
Career WAR: 3.9
Salvador Perez is quietly emerging as one of the American League's best all-around catchers. His contact hitting and throwing arm stand out as his most impressive tools.
The Venezuelan native tallied eight extra-base hits in 2013 spring training, which suggests he belongs in the heart of the Kansas City Royals lineup.
Do not be surprised if Perez sneaks onto the All-Star roster in his first full major league season.
Career WAR: 2.2
Several other young Atlanta Braves—who we'll discuss in later slides—often overshadow Freddie Freeman.
However, the first baseman is coming off consecutive 20-homer seasons and seeing the ball better than ever. An oblique injury has relegated him to the disabled list, but Freeman still has the opportunity to drive in 100 runs this summer. That hasn't been accomplished by any Braves batter since 2007.
He has gradually gotten comfortable against left-handed pitching. Anthony Rizzo must make the same adjustments if he hopes to overtake Freeman.
Career WAR: 2.3
Second base is almost entirely devoid of promising young talent. Beyond the Houston Astros, only the Colorado Rockies and San Diego Padres start under-25 players at the position.
Jose Altuve has an effective contact swing and enough speed to cause disruptions on the basepaths. At the same time, his short stature limits his defensive range. Like seemingly every member of Houston's lineup, Altuve can be overaggressive at the plate.
Career WAR: 13.0
Elvis Andrus is beginning his fifth full MLB campaign, making him the most experienced player on this list.
He also has the highest salary. The All-Star shortstop recently agreed to a $120 million contract extension with the Texas Rangers. He'll earn $4.8 million in 2013 under the terms of his previous deal.
Andrus gets the nod over Starlin Castro due to his cleaner defense and efficient base-stealing. He has committed fewer errors despite more than 1,000 extra innings in the field.
Career WAR: 1.7
Manny Machado was actually a shortstop prospect who had only two games of professional experience at the hot corner prior to his call-up to the majors.
The Baltimore Orioles quickly observed that his quick reaction time and throwing accuracy made him a defensive stud at any position. So far on this young season, Machado has flaunted his athleticism with this diving grab and a barehanded assist (video courtesy of MLB.com).
Will Middlebrooks served as stiff competition for this spot on the under-25 team, especially with his recent three-homer performance (via ESPN.com). Machado's superior pitch recognition skills, however, will lead to special numbers as we get deeper into 2013.
The former top draft pick batted .262/.294/.445 as a 20-year-old last season.
Career WAR: 3.0
The 2012 NL Rookie of the Year was somewhat inconsistent for the Washington Nationals. He struggled to put balls in play from late June through early August.
But Bryce Harper—to borrow a motto from former teammate Mike Morse—went into "beast mode" over the final five weeks. With a 1.043 OPS and seven home runs from Sept. 1 onward, he allowed the Nats to run away with the NL East title.
The Las Vegas native has every tool and intangible imaginable, plus the plate discipline of a veteran player.
Career WAR: 11.2
Many analysts insist that Mike Trout's 2012 campaign was the most dominant for any MLB player since Barry Bonds.
He did everything. The young outfielder led baseball with 49 stolen bases while posting a batting line similar to Miguel Cabrera's. Also, MLB.com awarded Trout their GIBBY for Play of the Year for one of his many home-run-robbing catches.
Sabermetrics and traditional statistics agree that he's a unique talent who has the work ethic to avoid the dreaded sophomore slump.
Career WAR: 13.9
Going strictly by wins above replacement, Jason Heyward has contributed the most value among all under-25 guys during his brief time in the big leagues.
The Atlanta Braves don't take him for granted. They realize that players with his imposing physical build seldom steal 20 bases in a season or win a Gold Glove.
Heyward's numbers would be even more impressive if the Atlanta Braves didn't play home games at pitcher-friendly Turner Field. He averages a home run every 24 plate appearances as a visitor.
Career WAR: 12.0
Giancarlo Stanton has the qualifications to become the most expensive first-time arbitration-eligible player ever next winter.
He possesses the brute strength to knock out scoreboard panels (via MLB.com) and the consistency to hit 40 bombs in a full season. Stanton led the National League in slugging percentage a year ago despite seeing very few pitches to hit amid a weak Miami Marlins lineup.
Though he ranks among the sport's best active sluggers, we can't overlook his decent mobility, either (16 career stolen bases).
Career WAR: 6.6
Clayton Kershaw is the only pitcher this millennium with more major league starts and a lower earned run average than Stephen Strasburg.
Tommy John surgery, fatigue and organizational precautions have limited Strasburg's impact. However, he's usually untouchable on the mound (.221 batting average against).
The right-hander pairs overpowering stuff with impeccable control unlike anyone this side of Justin Verlander. If kept on a long leash in 2013, he will challenge for the NL Cy Young Award.
Career WAR: 8.4
It took just one season in the rotation for Chris Sale to convince the Chicago White Sox that he deserved a $32.5 million extension.
The Florida Gulf Coast University alum has a slider that should be considered among the filthiest pitches being thrown today. It helped him strike out exactly a batter per inning in 2012.
Sale has leapfrogged Jon Lester and CC Sabathia in the southpaw power rankings. Along with David Price, he's one of the top two left-handers in the American League.
Bruce Bochy consoles Bumgarner after he only went eight innings.
Career WAR: 8.8
Likewise, Madison Bumgarner has tens of millions in guaranteed dollars coming his way later this decade.
Performing regularly in cavernous AT&T Park means his stats could be somewhat misleading, but there's no doubt that he's elite for his age group.
Bumgarner's lifetime 3.90 strikeout-to-walk ratio is better than Roy Halladay's or Cliff Lee's. His typical start in the majors lasts six and one-third innings.
Ultimately, the North Carolina native distinguishes himself from other young talents with his World Series success. He has hurled 15 scoreless frames in his two career starts under the brightest lights.
Harvey might be the ace of an injury-torn Mets starting rotation.
Career WAR: 1.8
A handful of under-25 relievers have more innings pitched in Major League Baseball than Matt Harvey.
He is included on this team due to the sheer dominance of his first 11 starts for the New York Mets. Harvey has lasted at least five innings in every outing and totaled double-digit strikeouts on three occasions. Moreover, this 6'4" specimen is a .333/.333/.429 hitter since debuting last July.
His annihilation of the San Diego Padres on April 3 (via MLB.com) was as remarkable as anything we've seen in the Senior Circuit in 2013.
Career WAR: 1.1
Unlike most American-born players we've identified, Matt Moore was not coveted as an amateur. Playing high school ball in New Mexico kept this left-hander away from top-flight competition, and the Tampa Bay Rays were able to wait around until the eighth round of the 2007 draft to select him.
Moore has gradually become less dependent on his mid-90s fastball and incorporated more two-seamers and off-speed pitches into his game plan. He didn't contend for 2012 AL Rookie of the Year as expected, but his results drastically improved as the summer progressed.
Unlike, say, Jarrod Parker or Chris Tillman, he doesn't rely on balls in play. The potential to excel against any given opponent enabled Moore to claim the fifth starter's spot on this under-25 team.
Career WAR: 3.3
Craig Kimbrel will age out of this list on May 28. By then, he'll almost certainly have surpassed 100 career saves.
He's seeking a third straight season of 100-plus strikeouts out of the bullpen. That hasn't been done since Brad Lidge (2004-2006).
If any reliever earns a Cy Young Award in the next decade, it will be Kimbrel.