The Year of the Rookie?
June 23, 2010

This year has seen the remarkable debuts of Stephen Strasburg, Starlin Castro and Jason Heyward, as well as the major league introductions of a few other promising stars.  With the recent promotion of Dayan Viciedo in the hope of recharging the White Sox offense with a stalwart at third, I wondered if this year was destined to be viewed as historically great in terms of introducing the baseball world to future Hall of Famers.  But then it occurred to me that it is not rookies I should be looking at - since rookies can technically be 29-year old journeymen as well as interlopers from Japan.  No, the focus should be on young players.  Supporting that notion is the fact that the percentages show that the younger a player is when making his debut and staying in the majors, the better his chances are of becoming a star player.  So is 2010 a particularly good year for young players?

Well, in terms of sheer numbers, it's not bad.  But in quality, it's definitely one of the better years of the last decade.  Below is a listing by year of all the players 21 and younger who were playing in the majors before the All-Star Break in a given year.  The reason I chose that criteria is to omit the September call-ups, which can distort the analytic value of the debut as some teams are interested in winning now and can't afford to give young players a try despite them clearly being major league talented, whereas others are already looking to next year and may be willing to risk a young player making the transition.  But before the All-Star Break, at least in theory every team is pretty much trying to put their best team on the field.  Some of the guys listed were obviously rushed and/or perhaps no more than minor league talents whose ability will never translate to major league competition.  Others will be very familiar names that are currently being bandied about for All-Star consideration.

Elvis Andrus        TEX 
Starlin Castro      CHC 
Jason Heyward       ATL 
Jose Tabata         PIT 
Ruben Tejada        NYM 
Mike Stanton        FLA 
Rick Porcello       DET 
Stephen Strasburg   WAS 
Jenrry Mejia        NYM
Dayan Viciedo       CHW

Trevor Cahill       OAK 
Rick Porcello       DET
Sean O'Sullivan     LAA 
Justin Upton        ARI 
Elvis Andrus        TEX 
Travis Snider       TOR 
Fernando Martinez   NYM 
Clayton Kershaw     LAD 
Nick Adenhart       LAA 
Brett Anderson      OAK 

Jay Bruce           CIN 
Chris Volstad       FLA 
Justin Upton        ARI 
Phil Hughes         NYY 
Nick Adenhart       LAA 
Clayton Kershaw     LAD 
Ryan Tucker         FLA 
Jaime Garcia        STL 

Billy Butler        KAN 
Delmon Young        TAM
Felix Hernandez     SEA 
Carlos Gomez        NYM 
Homer Bailey        CIN 
Yovani Gallardo     MIL
Ryan Feierabend     SEA 
Phil Hughes         NYY 
Sean Gallagher      CHC 


Ryan Zimmerman      WAS 
Matt Kemp           LAD 
Melky Cabrera       NYY 
Chad Billingsley    LAD 
Lastings Milledge   NYM 
Joel Guzman         LAD 
Yusmeiro Petit      FLA 
Matt Cain           SFO
Felix Hernandez     SEA 
Joel Zumaya         DET 
Fabio Castro      TEX/PHI 
Boone Logan         CHW 

Zack Greinke        KAN 
Rene Rivera         SEA 
Prince Fielder      MIL 
Brian McCann        ATL 
Jeff Francoeur      ATL 
Pedro Lopez         CHW 
Jose Lopez          SEA 
Melky Cabrera       NYY 
Kyle Davies         ATL 
Andy Marte          ATL 
Scott Kazmir        TAM
Huston Street       OAK 
Marcos Carvajal     COL 
Brandon McCarthy    CHW 
Ambiorix Burgos     KAN 
Leo Nunez           KAN 
Yorman Bazardo      FLA 
Hayden Penn         BAL 
Scott Olsen         FLA 

Edwin Jackson       LOS
Joe Mauer           MIN
Miguel Cabrera      FLA
Andres Blanco       KAN
Yadier Molina       STL
Casey Kotchman      ANA
Jose Reyes          NYM
Sean Burnett        PIT
Jeremy Bonderman    DET
Edgar Gonzalez      ARI
Ryan Wagner         CIN
Chad Gaudin         TAM
Zack Greinke        KAN
Justin Germano      SDG
Elizardo Ramirez    PHI
Arnie Munoz         CHW
Travis Blackley     SEA

Rocco Baldelli      TAM
Carl Crawford       TAM
Oliver Perez      PIT/SDG
Jose Reyes          NYM
Edgar Gonzalez      ARI
Miguel Cabrera      FLA
Omar Infante        DET
Brandon Phillips    CLE
Jhonny Peralta      CLE
Dontrelle Willis    FLA
Enrique Cruz        MIL 
Wily Mo Pena        CIN 
Jerome Williams     SFO
Francisco Rodriguez ANA 
Jeremy Bonderman    DET
Oscar Villarreal    ARI

Jake Peavy          SDG
Mark Prior          CHC
Sean Burroughs      SDG
CC Sabathia         CLE
Hank Blalock        TEX
Chris Snelling      SEA
Nick Neugebauer     MIL
Oliver Perez        SDG
Carlos Zambrano     CHC
Miguel Asencio      KAN
Jung Keun Bong      ATL

Albert Pujols       STL
Cesar Izturis       TOR
Luis Rivas          MIN
Corey Patterson     CHC
Rick Ankiel         STL
Jon Garland         CHW
CC Sabathia         CLE
Bud Smith           STL
Ben Johnson         MON


T.J. Tucker         MON
Rick Ankiel         STL
Adrian Beltre       LOS
Ruben Quevedo       CHC
Aramis Ramirez      PIT 
Gookie Dawkins      CIN
Luis Matos          BAL
Ben Johnson         MON
Byung-Hyun Kim      ARI
Gil Meche           SEA
Jon Garland         CHW 
Luis Rivera       BAL/ATL
Johan Santana       MIN 
Tim Drew            CLE
Jason Marquis       ATL