As the season approaches the halfway point, I thought it would be instructive to check out how the rookies have performed in both the American and National Leagues. What I found of most interest is the fact that the AL seems to have the upper hand when it comes to pitchers and the NL with respect to hitters.

In total, there is a lot of talent in both leagues. The Rookie of the Year races are wide open but seem to be limited to the pitchers in the AL and the hitters in the NL.

Let's take a look at the stats through the conclusion of most games on Wednesday, June 21. I'll start off with the group that may be the weakest of the four.

AL ROOKIE HITTING STATS (Min. 100 PA)

PLAYER          TEAM  AB  R  H 2B 3B HR RBI SB BB  AVG  OBP  SLG  OPS 
Mike Napoli      LAA  93 19 27  5  0  7  15  2 18 .290 .416 .570 .986 
Ian Kinsler      Tex  94 16 30  7  1  5  21  2 10 .319 .385 .574 .960 
Kenji Johjima    Sea 221 28 60 13  0  5  29  0 11 .271 .321 .398 .719 
Melky Cabrera    NYY 133 21 33  4  1  1  16  2 20 .248 .351 .316 .666
Brandon Fahey    Bal 108 16 29  1  1  2  16  2  4 .269 .307 .352 .659 
Kendry Morales   LAA 101 10 23  4  0  3  11  1  7 .228 .278 .356 .634 
Nick Markakis    Bal 181 21 42  7  1  2  16  0 19 .232 .312 .315 .627 
Brian Anderson   CWS 152 22 27  5  0  5  18  2 19 .178 .274 .309 .583 

Ian Kinsler and Mike Napoli are the only rookies in the American League enjoying standout seasons. Kinsler, who turns 24 today, dislocated his left thumb in early April and missed more than six weeks. He slugged two home runs in his first game back and has gone deep twice since, giving the second baseman a total of five in less than 100 AB.

Napoli began the year at Triple-A Salt Lake and didn't make his MLB debut until May 4 when he became the 92nd player to homer in his first at-bat, connecting off fellow rookie Justin Verlander of the Detroit Tigers. The 24-year-old catcher, who led the Texas and California leagues in home runs the previous two seasons, is number one among AL rookies with seven cranks and has a superb OBP of .416.

NL ROOKIE HITTING STATS (Min. 100 PA)

PLAYER          TEAM  AB  R  H 2B 3B HR RBI SB BB  AVG  OBP  SLG  OPS 
Dan Uggla        Fla 265 49 83 11  4 13  43  4 20 .313 .366 .532 .899 
Prince Fielder   Mil 258 35 76 20  1 14  40  5 23 .295 .351 .543 .894
Russell Martin    LA 132 20 40  8  2  4  27  0 15 .303 .376 .485 .861 
Mike Jacobs      Fla 212 25 58 17  0 10  38  2 30 .274 .365 .495 .860
Andre Ethier      LA 112 15 33  6  1  4  15  1 10 .295 .360 .473 .833 
Josh Willingham  Fla 195 20 52 13  0  9  34  1 22 .267 .351 .472 .823
Willy Aybar       LA 106 14 29  9  0  3  20  1 12 .274 .364 .443 .807 
Ryan Zimmerman   Was 270 37 75 20  1 10  46  5 23 .278 .333 .470 .804 
Jeremy Hermida   Fla  98 14 26  7  1  2   8  2 14 .265 .368 .418 .787 
Ronny Paulino    Pit 171 17 54  9  0  2  15  0 15 .316 .369 .404 .772
Conor Jackson    Ari 198 30 52 11  0  6  38  0 28 .263 .355 .409 .764 
Hanley Ramirez   Fla 251 52 67 16  5  3  20 20 25 .267 .338 .406 .745
Josh Barfield     SD 231 30 58 11  2  4  19  8 11 .251 .287 .368 .655 
Nate McLouth     Pit 176 31 39 10  0  3   9  8 14 .222 .292 .330 .622 
Re. Abercrombie  Fla 170 23 37 10  1  3  14  3 14 .218 .280 .341 .621

The Marlins have six rookies playing everyday. Dan Uggla has not only been Florida's best first-year player but is in a good position to earn NL Rookie of the Year honors. Not as heralded as teammates Jeremy Hermida, Mike Jacobs, Hanley Ramirez, or Josh Willingham, the 26-year-old second baseman is leading NL rookies in hits (83), batting average (.313), and OPS (.899).

Hermida was on the disabled list with a right hip flexor from April 18 to May 23. The 22-year-old outfielder is starting to play well, going 16-for-55 with six doubles in June (including a walk in each of his last five games).

Hitting only .177 on May 7, Jacobs has turned his season around and raised his average by nearly 100 points. The 25-year-old first baseman is hitting .404/.456/.750 in June. He has slugged 24 doubles and 21 home runs in 312 career at-bats. However, Mike's value may be limited to a platoon role unless he begins to hit LHP better than the .122/.204/.204 line he has put up in 2006.

Ramirez got off to a hot start but is just 2-for-40 in his last 11 games. The toolsy shortstop was batting .344 on May 22 but has had only one two-hit game in the past month. Although ripping LHP to the tune of .396/.482/.688, he is hitting just .236/.302/.340 vs. RHP. To his credit, Ramirez is seventh in the NL in pitches per plate appearance (4.13) and has drawn a walk 9% of the time.

Willingham was placed on the 15-day disabled list last week, retroactive to June 7, with a left hand injury. He could be activated today. The 27-year-old left fielder went yard in his last two games. Call yourself fortunate if you have him as a catcher on your fantasy team.

Aside from the Marlins, the Dodgers are playing the most rookies in the NL this year. Willy Aybar, who was recently sent back to Las Vegas despite hitting .274/.364/.443, Andre Ethier (.295/.360/.473), and Russell Martin (.303/.376/.485) have already exceeded 100 plate appearances while Matt Kemp slugged seven HR in his first 15 games in the big leagues and is now an everday fixture in the starting lineup.

Prince Fielder and Ryan Zimmerman are also vying for NL ROY honors. Fielder and Zimmerman gave glimpses of what was to come last year when the Milwaukee first baseman hit .288 with two HR in 59 AB and the Washington third sacker batted .397 with 10 doubles in only 20 games. They have each slammed 20 two baggers this year. The 22-year-old Fielder leads all rookies with 14 HR and the 21-year-old Zimmerman sits atop the RBI leaderboard with 46.

AL ROOKIE PITCHING STATS (Min. 25 IP)

PLAYER          TEAM   IP  H  R ER BB SO W L SV  ERA WHIP   K/9  K/BB 
Jon Papelbon     Bos 35.2 19  1  1  4 35 1 1 23 0.25 0.64  8.83  8.75
Jered Weaver     LAA 26.1 16  5  4  4 22 4 0  0 1.37 0.76  7.52  5.50
Zach Miner       Det 26.0 19  8  6  7 13 3 1  0 2.08 1.00  4.50  1.86
Fran. Liriano    Min 58.1 47 14 14 17 67 6 1  1 2.16 1.10 10.34  3.94
Joel Zumaya      Det 35.1 19  9  9 17 45 3 0  1 2.29 1.02 11.46  2.65
James Shields     TB 30.0 32 10 10 10 27 4 0  0 3.00 1.40  8.10  2.70
Bobby Jenks      CWS 29.2 26 10 10  9 36 2 1 20 3.03 1.18 10.92  4.00
Sendy Rleal      Bal 31.2 28 13 11 17 12 1 1  0 3.13 1.42  3.41  0.71
Justin Verlander Det 89.2 84 34 32 28 53 8 4  0 3.21 1.25  5.32  1.89
John Rheinecker  Tex 30.0 38 12 12  5 16 2 1  0 3.60 1.43  4.80  3.20
Bobby Keppel      KC 29.2 32 12 12 12 15 0 3  0 3.64 1.48  4.55  1.25
Ruddy Lugo        TB 42.1 36 18 18 20 24 1 5  0 3.83 1.32  5.10  1.20
Casey Janssen    Tor 62.0 62 33 31 12 32 5 5  0 4.50 1.19  4.65  2.67
Jake Woods       Sea 29.1 25 17 16 19 25 1 1  1 4.91 1.50  7.67  1.32
Fausto Carmona   Cle 31.0 32 17 17 10 25 1 2  0 4.94 1.34  7.47  2.60
John Koronka     Tex 81.0 89 45 45 30 38 5 4  0 5.00 1.47  4.22  1.27
Boof Bonser      Min 26.1 30 17 17  8 22 1 1  0 5.81 1.44  7.52  2.75

What can you say about the rookie pitchers in the AL? Francisco Liriano, Jonathan Papelbon, Justin Verlander, Jered Weaver, and Joel Zumaya have been lights out thus far. In fact, Liriano and Papelbon have been so dominant that either one could wind up winning the Cy Young Award almost as easily as Rookie of the Year. The 22-year-old Liriano (6-1, 2.16 ERA) makes his seventh start of the year tonight against a guy named Roger Clemens. Set your DVR now.

Papelbon (1-1, 0.25, and 23 saves) has been the best closer in either league during the first three months of the current campaign. The 25-year-old RHP has allowed only 24 baserunners and one run in 36 innings of work. Opponents are hitting--if you can call it that--.153/.186/.185 against him.

Verlander and Zumaya, both of whom can hit triple digits on the radar gun, are two reasons why the Detroit Tigers have the best record in baseball. Verlander, 23, has won eight games and ranks fifth in the AL in ERA (3.21). The 21-year-old Zumaya lost his first game of the year last night but has struck out 45 batters in 35.2 IP while leading the league in holds with 17.

Weaver made his MLB debut on May 27 and proceeded to beat the Baltimore Orioles, Cleveland Indians, Tampa Bay Devil Rays, and Kansas City Royals in his first four starts before managing to get sent back down to the minors on June 17. The 23-year-old RHP didn't allow more than five hits, two walks, or two runs in any game while limiting opponents to an OPS of .489 or .047 lower than the worst-hitting regular in the majors this year.

James Shields is off to a fantastic start. The 24-year-old won his fourth game without a loss last night and has yet to give up a home run in 30 innings while inducing twice as many groundballs as flyballs. Shields has a major-league quality changeup and could be a solid starter if he continues to command his fastball the way he has this month.

Bobby Jenks (2-1, 3.03 ERA, 20 saves) has been among the best closers in the league this year. The hard-throwing righthander earned his fame last fall when he helped the White Sox win their first World Series championship since 1917.

Boston's Jon Lester and Craig Hansen are two prized prospects to keep close tabs on, and Cleveland's Jeremy Sowers will be making his MLB debut against the Cincinnati Reds on Sunday. The latter was 8-1 with a 1.27 ERA for Buffalo. The 23-year-old Sowers was 14-4 with a 2.37 ERA at three levels in his first season of professional baseball last year.

NL ROOKIE PITCHING STATS (Min. 25 IP)

PLAYER          TEAM   IP   H  R ER BB SO W L SV  ERA WHIP   K/9  K/BB
Takashi Saito     LA 34.2  20  7  7  8 45 3 2  4 1.82 0.81 11.68  5.63
Josh Johnson     Fla 67.0  53 21 15 32 59 6 4  0 2.01 1.27  7.93  1.84
Ramon Ramirez    Col 31.0  18  8  8  6 31 2 1  0 2.32 0.77  9.00  5.17
Brian Sweeney     SD 34.1  32 10  9 11 12 2 0  1 2.36 1.25  3.15  1.09
Adam Wainwright  StL 33.2  22  9  9  6 28 2 1  1 2.41 0.83  7.49  4.67
Shawn Hill       Was 26.0  22  8  7  9 12 1 1  0 2.42 1.19  4.15  1.33
Jonathan Broxton  LA 26.2  20  9  8 12 34 1 0  0 2.70 1.20 11.48  2.83
Brian Bannister  NYM 28.0  22  9 9  17 14 2 0  0 2.89 1.39  4.50  0.82
Alay Soler       NYM 33.0  25 13 11 13 19 2 1  0 3.00 1.15  5.18  1.46
Ken Ray          Atl 32.2  26 11 11 15 23 0 0  4 3.03 1.26  6.34  1.53
Ricky Nolasco    Fla 53.0  56 24 18 16 41 5 3  0 3.06 1.36  6.96  2.56
Mike O'Connor    Was 63.0  46 28 24 29 44 3 4  0 3.43 1.19  6.29  1.52
Enrique Gonzalez Ari 27.0  19 11 11  6 21 2 0  0 3.67 0.93  7.00  3.50
Clay Hensley      SD 80.0  69 36 36 35 38 4 5  0 4.05 1.30  4.27  1.09
Matt Capps       Pit 35.2  37 17 17  5 28 2 1  0 4.29 1.18  7.07  5.60
Jose Capellan    Mil 38.2  33 20 19 13 29 2 0  0 4.42 1.19  6.75  2.23
Paul Maholm      Pit 82.0 101 42 41 41 56 2 5  0 4.50 1.73  6.15  1.37
Mike Thompson     SD 39.0  42 22 20 10 17 3 2  0 4.62 1.33  3.92  1.70
Scott Olsen      Fla 67.0  60 38 35 29 58 6 3  0 4.70 1.33  7.79  2.00
Fernando Nieve   Hou 65.0  64 35 34 20 42 2 3  0 4.71 1.29  5.82  2.10
Matt Cain         SF 77.0  66 45 41 34 62 6 5  0 4.79 1.30  7.25  1.82
Cole Hamels      Phi 25.2  22 15 14 14 25 1 2  0 4.91 1.40  8.77  1.79
Sean Marshall    ChC 76.0  70 42 42 36 50 4 5  0 4.97 1.39  5.92  1.39
Angel Guzman     ChC 25.1  24 18 16 20 29 0 2  0 5.68 1.74 10.30  1.45
Taylor Buchholz  Hou 77.1  78 52 50 19 47 4 6  0 5.82 1.25  5.47  2.47

Josh Johnson (6-4, 2.01 ERA) and Takashi Saito (3-2, 1.82, 4 saves) have been the top-performing rookie starter and reliever, respectively, in the NL this year. The 22-year-old Johnson began the season in the bullpen and didn't earn his first start until May. He hasn't allowed over three runs in any game and has held the opposition to no more than two runs in eight of his nine starts. Johnson has struck out almost 8 per 9 IP while giving up just two homers over the course of 67 frames.

While it is hard to think of the 36-year-old veteran of Japanese baseball a rookie, Saito qualifies as a first-year player here in the States. He has performed admirably as both a set-up man and closer for the Dodgers. The RHP is averaging 11.7 Ks per 9 while limiting opponents to a .168/.219/.277 hitting line.

In the department of the best of the rest, Matt Cain, as a whole, hasn't pitched up to expectations yet but nearly tossed a no-hitter against the Angels in his last start to go along with a one-hit shutout vs. the A's a month ago. The 21-year-old has a huge ceiling and could wind up as the best of the lot five or ten years from now. Chad Billingsley, Cole Hamels, and Anthony Reyes are three other rookie starters to watch closely.

My sense is that 2006 is going to be remembered as a year in which a number of great--not good--players began their MLB careers.

[Additional reader comments and retorts at Baseball Primer.]