The 2004 Cincinnati Reds had an opening-day roster with not one first-year player on it. That's not that unusual. However, the Reds proceeded to play over 130 games, brought players up, traded for players, expanded their roster for September, and yet did not add one player to the roster who had never played in the majors before.

Then on September 4, the picked up rookie pitcher Juan Padilla on waivers from the Yankees. Padilla is a rookie (I'm using the term "rookie" to mean first-year player throughout, though baseball has a more technical definition to determine eligibility for the Rookie of the Year awards). However, Padilla did pitch six games earlier in the year for the Yankees.

That means that the Reds will likely spend the entire season without a player appearing in his first major-league game. That seems pretty unusual but is it? Let's check.

Here are all of the teams throughout baseball history who qualify in descending chronological order:

It's happened just thirty-three times, and just twice in the last twenty seasons. That's pretty rare.

You'll also notice that for the most part these teams have been pretty successful veteran clubs. Only four had sub-.500 seasons, and their average winning percentage is .597. The 2004 Reds don't fit that mold. Usually when a team has a losing season for the second year in a row, like the Reds, they try some new blood. Unfortunately, the Reds were fooled by their first-season success momentarily and apparently don't have much fresh meat in the minors.

Now, the Reds are also not the first team on the list to have one first-year player who first played with another major-league team earlier in the year. The 1889 American Association Brooklyn Bridegrooms (grandsire of today's Los Angeles Dodgers) had one first-year player, Charlie Reynolds, a catcher who played one game on May 8 with the AA Kansas City Cowboys before appearing in 12 Brooklyn contests.

The 1881 NL Cleveland Blues had a player, Bollicky Bill Taylor, a pitcher-outfielder-third baseman who appeared in games for the Worcester Ruby Legs (forerunners of the Phillies, 6 games) and Detroit Wolverines (1) earlier in the season. Taylor went on to win 43 games in 1884 as the majors expanded briefly to three major-leagues but would only win a total of fifty for his career. He also managed to squeeze in 61 games behind the plate though he apparently was not a catcher when he came up.

All of this rookie talk got me to thinking of the reverse. Were there any teams comprised solely of rookies, and how did they fare? We'll it's kind of a trick question. Here's the answer:

Well, when you're the first major league, everybody who plays for you will be a rookie. How about the next highest percentage of rookies? Here are the ones over 75%:

Still, these are old teams, many from new leagues. How about in the "modern" era? Here are the ones since 1900 comprised 50% or more of rookies:

The highest since 1950 were the second-year 1963 Houston Colt .45s nee Astros at 44.44% (20 of 45 players). Here are the highest since 1950. Note that the post-World Series Marlins had the highest percentage of rookies in the last ten years:

You may also notice that teams with a high percentage of rookie players are just not that good. Very few have winning records. I ran the numbers to see if a high percentage of rookies correlates to a poor winning percentage. Basically, do (mostly) veteran teams perform better? Well, it does correlate but not very strongly (.335 correlation coefficient). I guess it's best to get the better players no matter what experience level they are. Eventually, I'll expand this study to look at veteran teams based on years of experience and see if that corresponds better to winning, but that will have to be another day.