MLB Prospect Watch: Picking the All-20-and-Under Team

With baseball nearing its midway point in the 2011 season, some teams will need to shuffle up their lineups if they plan on making a run late in the season to win their respective division or their league's Wild Card.

Keeping that in mind, here is a list of the top players under 20-years-old who have a possibility of being called up late this season or making their major league debuts within the next couple of years.

Regardless of when they're called up to the big leagues, these players will make an immediate impact.

Starting Pitcher: Julio Teheran

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LAKE BUENA VISTA, FL - FEBRUARY 21: Julio Teheran #66 of the Atlanta Braves during Photo Day at Champion Stadium at ESPN Wide World of Sports of Complex on February 21, 2011 in Lake Buena Vista, Florida. (Photo by Mike Ehrmann/Getty Images)

Although Julio Teheran, the Atlanta Braves' 20-year-old top prospect, has struggled in the two starts he made for the team this season, there is still much talk about the future of this young ace.

After spending the first few years of his career playing for the Braves' Single-A affiliate, Teheran spent much of last season pitching for Rome, Myrtle Beach and Mississippi, and finished the season with a 9-8 overall record and a 2.59 ERA.

This season, Teheran was named to the team's Triple-A club, where he is currently 7-1 with a 1.83 ERA with 68 strikeouts in 78.2 innings pitched.

Starting Pitcher: Jameson Taillon

The Pittsburgh Pirates drafted Jameson Taillon with the second overall pick in last year's draft after he had an impressive senior year at The Woodlands High School in Texas, a season that saw Taillon finish 8-1 and throw a 19-strikeout no-hitter.

Although Taillon is only 19-years-old, the Pirates expect him to be the ace of their rotation after he spends a few more years in the minor leagues.

Currently, Taillon is playing for the Pirates' Low-A West Virginia Power, where he is 2-1 with a 3.16 ERA and 38 strikeouts in 10 starts and just under 43 innings pitched.

Starting Pitcher: Shelby Miller

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JUPITER, FL - FEBRUARY 24: Shelby Miller #71 of the St. Louis Cardinals during Photo Day at Roger Dean Stadium on February 24, 2011 in Jupiter, Florida. (Photo by Mike Ehrmann/Getty Images)

The St. Louis Cardinals drafted pitcher Shelby Miller out of high school with the No. 19 overall pick in the 2009 MLB Draft.

Miller began the 2011 season at the Cardinals' High-A Palm Beach club, but after going 2-3 with a 2.89 ERA and recording 81 strikeouts in only 53 innings pitched, he was promoted to the team's Double-A ball club.

Currently, Miller is 3-0 with Double-A Springfield, with a 1.38 ERA and 25 strikeouts in 26 innings.

If he continues to pitch at this pace, he could end up pitching in St. Louis by next season.

Starting Pitcher: Jacob Turner

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LAKELAND, FL - FEBRUARY 21: Jacob Turner #50 of the Detroit Tigers poses for a portrait during Photo Day on February 21, 2011 at Joker Marchant Stadium in Lakeland, Florida. (Photo by Nick Laham/Getty Images)

Jacob Turner was drafted ninth overall in the 2009 MLB Draft and had already landed on the Detroit Tigers' 40-man roster by November of that same year.

While playing for the Tigers' A and High-A affiliates in 2010, Turner went 6-5 with a 3.28 ERA and 102 strikeouts in 24 games that season.

This season with the Tigers' Double-A Erie SeaWolves, Turner is 2-1 in 12 starts and has recorded 64 strikeouts in 79.2 innings pitched.

Starting Pitcher: Martin Perez

In 2007, the Texas Rangers signed left-handed pitcher Martin Perez as an undrafted free agent and immediately sent him the Rookie-Level Spokane Indians, where he went 1-2 with a 3.65 ERA in 15 starts for the team.

The following season, Perez spent time with the Rangers' Single and Double-A ball clubs, and he finished the year 6-8 with a 2.90 ERA and 119 strikeouts in 114.2 innings pitched.

Currently, Perez, only 19-years-old, is still pitching for the Rangers' Double-A team, where he is 4-1 with a 3.30 ERA and 73 strikeouts in 14 starts.

Catcher: Gary Sanchez

In 2009, the New York Yankees took a chance on then 16-year-old catcher Gary Sanchez and signed him as an international free agent.

Sanchez spent the 2010 season playing for the Yankees' Rookie-Level and Low-A ball clubs, where he posted a combined .329 batting average, hit eight home runs and drove in 43 RBI.

Sanchez is off to a strong 2011 season as well, as he is currently batting .267 with five home runs and 25 RBI in 44 games with the Single-A Charleston RiverDogs.

First Base: Jonathan Singleton

The Philadelphia Phillies drafted first baseman Jonathan Singleton in the eighth round of the 2009 MLB Draft and have already gotten more than they expected in return from the future major leaguer.

While playing for the Phillies' Class-A Lakewood Blue Claws in 2010, Singleton hit 14 home runs and drove in 77 runs en route to finishing with a .290 batting average and a .393 OBP.

This season, Singleton is playing for the Phillies' High-A Clearwater Threshers and currently has a .244 batting average, three home runs and 21 RBI in 57 at-bats with the team.

Note: The Phillies have started to groom Singleton into an outfielder because of the recent long-term deal they signed All-Star Ryan Howard to. But because Singleton is still playing both positions this season, he falls into the first base category on this list.

Second Base: Kolten Wong

Kolten Wong, 20, was the No. 22 overall selection in the 2011 MLB Draft by the St. Louis Cardinals out of the University of Hawaii.

Most of the top prospects on Keith Law's Top 100 Prospects list are either moving from second base to shortstop or are too old to make this list, so Wong gets the spot.

A career .358 hitter, Wong looks like a bright up-and-coming prospect for the Cardinals, and one the best young second basemen in the game.

While at Hawaii, Wong hit 47 doubles, 25 home runs and drove in 145 runs while slugging .563 and stealing 53 bases. He was a three-time First-Team All-WAC player and MVP of the Cape Cod Summer League.

His strong left-handed bat should provide support to the Cardinals' lineup a few years down the road.

Shortstop: Manny Machado

Manny Machado was drafted No. 3 overall in the 2010 MLB Draft by the Baltimore Orioles after hitting .639 with 12 home runs and 68 RBI in his 29 game senior season at Brito High School in Florida.

Machado is currently playing for the Orioles' Single-A Delmarva Shorebirds, where he is batting .276 with six home runs and 24 RBI in 38 games with the team.

Although Machado is primarily a shortstop, he has also spent time serving as a designated hitter, which makes him even more of a threat for the Orioles in the future.

Third Base: Miguel Sano

The Minnesota Twins signed Miguel Sano out of the Dominican Republic in September 2009 and are already talking of Sano as the replacement for current third baseman Danny Valencia.

While playing in both the Dominican Summer League and the Gulf Coast League in 2010, Sano hit a combined .307 with seven home runs and 29 RBI in 61 games.

Sano is a big, fast and athletic player that has led scouts to compare him to Marlins slugger Hanley Ramirez.

A 2012 major league debut has been tossed around by the Twins organization, as Sano would be 19 and have two full minor league seasons under his belt.

Outfield: Mike Trout

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TEMPE, AZ - FEBRUARY 21: Mike Trout #90 of the Los Angeles Angels of Anaheim poses during their photo day at Tempe Diablo Stadium on February 21, 2011 in Tempe, Arizona. (Photo by Rob Tringali/Getty Images)

Mike Trout, currently 19-years-old, was drafted by the Los Angeles Angels 25th overall in the 2009 Draft and was even previously ranked as the top prospect in baseball by ESPN's Keith Law.

While playing for the Arizona League Angels in 2009, Trout hit .360 with one home run, 25 RBI and 13 stolen bases in only 39 games.

After posting impressive numbers at Angels' Single-A Cedar Rapids club, Trout was promoted to Class-A Advanced Rancho Cucamonga where he won the Topps Player of the Year Award.

Outfield: Bryce Harper

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VIERA, FL - FEBRUARY 25: Bryce Harper #34 of the Washington Nationals poses for a portrait during Spring Training Photo Day at Space Coast Stadium on February 25, 2011 in Viera, Florida. (Photo by Al Bello/Getty Images)

Bryce Harper is only 18-years-old, but already the hopes of the entire Washington Nationals organization have been placed on his shoulders after a late-season injury to pitcher Stephen Strasburg put his future in jeopardy.

Harper has been called the best hitting prospect since Alex Rodriguez and has put up numbers that back up that statement throughout his young career.

While enrolled at the College of Southern Nevada, a school that uses wooden bats, he hit a school-record 31 home runs and drove in 98 runs in only 66 games.

Outfield: Wil Myers

In what may have been the steal of the 2009 MLB Draft, the Kansas City Royals selected Wil Myers with their third round, 91st overall pick.

At age 20, Myers has already developed into one of the top prospects in all of baseball. While playing in the Royals' Rookie Leagues in 2009, Myers hit .369 with five home runs in only 84 at-bats.

After spending the 2010 season in both the Carolina and Midwest Leagues, Myers finished the year batting a combined .315 with 14 home runs and 83 RBI.

Prior to the start of this season, the Royals announced that, although Myers has spent much of his career as a catcher, he would be moving into the outfield.