AaronGleeman.com

Check out his numbers from 2001, 2002 and his projected 2003 totals:

  G      AB      PA      AVG      OBP      SLG     HR     2B

114     381     407     .289     .322     .441      7     33

130     440     469     .300     .334     .439      6     31

136     492     528     .301     .339     .457     12     30

That is remarkable consistency. He has gradually increased his playing time behind the plate and has also increased his power slightly, all while maintaining very good batting averages each year. It all adds up to a catcher who is a career .297/.334/.443 hitter, which is pretty impressive.

This season, Pierzynski has gotten the second-most playing time among American League catchers (behind only Jorge Posada) and he ranks 4th among AL catchers in "Runs Above Replacement Position," with 20.6 RARP. Defensively, he's not great - he struggles blocking balls in the dirt at times and doesn't have a particularly good arm - but his defense is certainly acceptable.

The durability, the consistency, the defense, the hitting - put it all together and add in a really long name and you get one of the top 5-7 catchers in all of baseball over the past 3 seasons. Make no mistake, A.J. Pierzynski has been one of Minnesota's most valuable players over the last few years and is a big part of their turnaround as a franchise. He is also just 26 years old.

With all that said, the Twins have a guy in Double-A right now who, when he's ready, will end Pierzynski's days as the Twins' starting catcher faster than you can spell P-I-E-R-Z-Y-N-S-K-I (assuming, of course, that you can actually spell it at all).

Joe Mauer, the #1 overall pick in the 2001 draft, is living up to all the hype and expections so far, and is hitting so well in Double-A that he has me thinking about the future of Twins catching, even while the present includes one of the best catchers in the league.

Mauer signed quickly in 2001, played rookie-ball that year, and then spent last season in low Single-A. This year, he started out at high Single-A, before being promoted to Double-A. All of which means he has made 4 stops in his professional career thus far.

Here are his batting averages at those 4 stops:

.400

.302

.335

.359

Not bad, huh?

For his minor league career, Mauer has 316 hits in 949 at bats, which works out to an absolutely beautiful .333 batting average. To go along with the .333 average, Mauer also sports a career walk/strikeout ratio of 117/92, which is excellent. He gets rave reviews for his defense and game-calling behind the plate, and his throwing arm is among the best, if not the best, in minor league baseball.

That is a great resume for sure, but making everything even more impressive is the fact that Joe Mauer was born on April 19, 1983. That makes him about three and a half months younger than me, and it means he doesn't turn 21 years old for another 8 months or so.

Even if the Twins play it conservatively with Mauer - and I expect that they will - he is almost certainly on-track to make his major league debut within a few months of turning 21.

Age is, and always will be, one of the biggest keys for evaluating a prospect. A player's "tools" are important, as are his actual performances, but age is what puts everything into context. A 25 year old guy tearing up Single-A isn't anything to get excited about, but a 20 year old hitting .359 in Double-A is something that warrants its own entry on this blog.

Great baseball players generally make it to the major leagues at young ages. I'm not talking about good players like A.J. Pierzynski. I am talking about great players, Hall of Fame players, players like Pudge Rodriguez and Rickey Henderson, or Alex Rodriguez and Barry Bonds. Players like everyone in Minnesota is hoping Joe Mauer will turn out to be.

If you look at when Hall of Famers first got significant playing time (let's say 150+ plate appearances) in the major leagues, you get a list of guys who were very young. Here is a list of the last 30 position players to be elected to the Hall of Fame by The Baseball Writers of America Association, along with what age they first got significant playing time in the majors:

Eddie Murray             21

Gary Carter              21

Ozzie Smith              23

Dave Winfield            21

Kirby Puckett            23

Carlton Fisk             24

Tony Perez               23

George Brett             21

Robin Yount              18

Mike Schmidt             23

Reggie Jackson           22

Rod Carew                21

Joe Morgan               21

Johnny Bench             20

Carl Yastrzemski         21

Willie Stargell          23

Billy Williams           23

Willie McCovey           21

Lou Brock                23

Luis Aparicio            22

Harmon Killebrew         23

Brooks Robinson          21

Hank Aaron               20

Frank Robinson           20

Al Kaline                19

Duke Snider              21

Willie Mays              20

Eddie Mathews            20

Ernie Banks              23

Ralph Kiner              23

That's a long and distinguished list of great players and it stretches all the way back to guys who played in the 1940s. Without exception, every single one of those 30 players was getting significant playing time by the time they were 24 years old. In fact, 29 of the 30 were playing a lot by 23.

Not only did everyone but Carlton Fisk get extended playing time by 23, the majority of them were full-time, everyday starters by 23, and many of them sooner than that. 17 of those 30 players were getting significant playing time by age 21, which is what Mauer is on-track for.

The next wave of Hall of Fame hitters were all young everyday players as well. Tony Gwynn was 22, Wade Boggs was 24, Cal Ripken Jr. was 21, Mark McGwire was 23 and Paul Molitor was 21. Among current players who are likely future Hall of Famers - Barry Bonds, Rickey Henderson, Roberto Alomar, Ken Griffey Jr., Alex Rodriguez, Sammy Sosa, Frank Thomas, Rafael Palmeiro, Ivan Rodriguez - they were all everyday players by the age of 22.

It is just a fact that appears to be proven out throughout baseball history: Truly great players, the best of the best, all played big roles in the major leagues at early ages. That looks like it will bode well for Joe Mauer and it is a good sign for guys like Hank Blalock, Rocco Baldelli, Mark Teixeira and Adam Dunn, impressive players who are all starters at very young ages. For a 25 year old rookie like Angel Berroa however, history is not on his side, at least not if he has dreams of being a Hall of Famer some day.

For Mauer specifically though, the ages of outfielders and first basemen and shortstops aren't all that useful. Playing catcher is a unique job with many different challenges than players at other positions face, and I think it would make more sense to look at the top catchers in baseball history, to see at what ages they first got significant playing time in the majors.

Here is Bill James' ranking of the top 15 catchers of all-time from The New Bill James Historical Baseball Abstract, along with the age they first reached 150+ plate appearances in a season:

Yogi Berra               22

Johnny Bench             20

Roy Campanella           26

Mickey Cochrane          22

Mike Piazza              24

Carlton Fisk             24

Bill Dickey              22

Gary Carter              21

Gabby Hartnett           22

Ted Simmons              20

Joe Torre                20

Bill Freehan             21

Ivan Rodriguez           19

Thurman Munson           23

Elston Howard            26

Very similar to the list of the last 30 Hall of Famers. Of those 15 catchers, all but 2 of them were playing significant roles in the majors by the time they were 24 years old, and 10 of the 15 were doing so by 22.

The only two catchers who were not playing a lot in the majors by 24 were Roy Campanella and Elston Howard, who both made their major league debuts at age 26. The reason for their late major league debuts, of course, was the color of their skin. Campanella was the starting catcher for the Baltimore Elite Giants of the Negro League from 1937, at the age of 17, until 1945. Meanwhile, Elston Howard started catching for the Kansas City Monarchs in 1948, at the age of 19. Howard didn't even get a chance to start playing in the minor leagues until 1953, at which point he was already 24 years old.

So, if given a chance, Campanella and Howard would obviously have been everyday catchers in the major leagues well before they were 26, and most likely by the time they were 21 or 22, just like most of the other great catchers in baseball history.

Of course, just being young isn't going to get Mauer a ticket to Cooperstown. Heck, I'm 20 just like Mauer is (in fact, we both graduated from high school the same year and both attended schools in the St. Paul City Conference), but I don't think I'd have much of a shot at the HoF if the Twins stuck me behind the plate for the last 40 games of this season. No, along with his youth, Mauer is going to have to perform like the rest of those great players who debuted young.

Will he do that? Who knows. His minor league performances thus far are great and become even greater when considering his youth. He is very close to being the "complete package," but is definitely missing one large part of that package right now - hitting for power. In 949 career at bats in the minors, Mauer has hit just 9 home runs. He's still extremely young and power does tend to develop later than other skills, but 9 home runs in nearly 1,000 at bats is a very low total for a player who is big and strong, and who scouts have always projected to hit for big power.

For minor leaguers, particularly young ones, the home run totals are often not that impressive. Another thing to look at to try to project future power in a young player is the amount of doubles he hits. The theory being that, as he matures and adds strength, those doubles will start traveling a few extra feet and over fences.

Let's break Mauer's 3 minor league seasons down and see how often he has hit both homers and doubles:

Year      LVL     AB/HR     AB/2B

2001     Rook      ----      18.3    

2002     LowA     102.8      17.8

2003     A/AA      85.6      15.3

The doubles rate has been fairly consistent and is gradually improving. The home run rate is a little more interesting.

In 2001, Mauer hit .400 in rookie-ball, but didn't hit a single homer in 110 at bats. Last year, he hit 4 homers in 411 at bats. This season, he has 5 homers in 428 at bats thus far. 5 long balls in 428 at bats is not impressive, even for a 20 year old in Double-A, but it is a significant improvement over his home run numbers from his first 2 seasons. Also, 4 of his 5 homers this season have come since he was promoted to Double-A, so his Double-A home run rate is actually one per 48.75 at bats.

So, to break it down by level - Rookie, Single-A and Double-A - Mauer has the following home run and doubles rates:

 LVL     AB/HR     AB/2B

   R      ----      18.3

   A     128.8      16.5

  AA      48.8      13.0

Definitely encouraging progress.

I truly believe Joe Mauer is now the best prospect in baseball. Prior to this season, I ranked him as the #2 overall prospect in baseball, behind Mark Teixeira, who is now playing everyday for the Texas Rangers (at the age of 23). Teixeira is no longer a "prospect" and, even if he was, Mauer may have pushed past him on the basis of his outstanding season thus far.

Even if Mauer's power (geez, how many times are we gonna hear that when he's in the majors - "Mauer Power") never fully arrives, Joe Mauer is going to be a special player. He has shown the ability to hit for excellent batting averages wherever he has been, he is potentially a Gold Glove caliber defensive catcher and he has very good plate discipline and strike zone judgment. And, perhaps most impressively and most importantly, he is doing all of it at just 20 years old. His low-end projection right now would seem to me to be someone like Jason Kendall, a career .301/.384/.419 hitter and 3-time All-Star. His high-end projection? Who knows, I really do think the sky is the limit.

If he develops the great power that many feel he has the potential for, he could be a consistent .300+ hitter with excellent plate discipline, 30+ home run power and great defense behind the plate. No one really strikes me as a great comparison for those numbers because...well, those are some incredible numbers from a catcher. I mean, it sounds completely ridiculous to even say something like "Johnny Bench, but with a little better batting average" or "Mike Piazza, but with better defense" or "Ivan Rodriguez, but with better plate discipline." And that's why so many Twins fans, myself among them, are so damn excited about Joe Mauer.

No offense A.J., but you may want to rent and not buy, maybe get in touch with a travel agent, and see about getting yourself some nice luggage. And don't look back A.J., because there is something gaining on you.

Link of the Day:

Twins Geek - "He's a fan. He's a geek. It's kinda sad, really."

Today's picks:

Milwaukee (Franklin) +160 over Philadelphia (Duckworth)

Toronto (Halladay) -110 over Seattle (Garcia)