There is one rather salient little factoid that I left out of my analysis of Sammy Sosa moving to the Orioles. Should both Sosa and Rafael Palmeiro are both on the active roster at the same time, it will mark the first time in baseball history that two players on the same team have had 500 career home runs.

Sosa has 574, and Palmeiro 551. That's a total of 1125 career home runs. The previous high for two teammates was 1056, and it happened twice. Here are the top 25 teammates in career home runs (Remember, these numbers reflect the career homers as of the given year):

Note that Giants Barry Bonds (703) and Moises Alou (278, for a total of 981) should join this list this year. Also, both these tandems should add to their career totals throughout the year.

Even though this will be the first time two teammates will be in the 500-homer club, there have only been nine teams with two men in the 400-home run club:

However, this will not be the first time that two future 500-home run players have been on the same team. It won’t even add to the list of such teammates since Palmeiro and Sosa were teammates in Texas back in 1989, when Sosa was a 20-year-old rookie. He played 25 games in Texas before being traded to the White Sox on July 29. Palmeiro was just 24 and had never hit more than 14 homers in his four-year career.

Here is the complete list:

Finally, given that there have been so few 500-home run hitters, should we be surprised that no two teammates have ever before both reached the magic number. Consider that Babe Ruth was the first man to join the club in 1929. He was the sole active member until 1935. Then in 1940 Jimmie Foxx became the second man in the club. In Foxx's last season, 1945, Mel Ott became number three. Then Ott was the only active member until 1947. Ted Williams became the fourth member in his last season, 1960. Willie Mays joined them in 1965 and then both Mickey Mantle and Eddie Mathews in 1967, when there were three active 500-home run hitters for the first time.

Their ranks grew to four when Hank Aaron joined the list in 1968, Mantle and Matthews' last season. Ernie Banks became the third active member in 1970. Harmon Killebrew and Frank Robinson made it five active members for the first time in 1971. That decreased to four when Banks retired after 1971, three when Mays retired after 1973, and two when Killebrew retired after 1975.

By 1977, there were no active members. Then, just Willie McCovey, 1978-80 and just Reggie Jackson, 1985-86. Both Jackson and Schmidt were active members in 1987, the first time multiple members were active in over a decade. Then, it was just Schmidt for two seasons.

Baseball went six seasons without any new recruits to the club. Then, Eddie Murray was the sole active member for two seasons. By 1998, there were again no active 500-homerians. Mark McGwire joined their ranks in 1999. By 2001, McGwire's last season, Barry Bonds joined him. 2003, Palmeiro and Sosa joined Bonds. Finally, Ken Griffey made it four last season.

What this long dissertation of "begats" was supposed to demonstrate is how unlikely it is that two men in all of baseball let alone on one team were active members of the 500-homer run club at the same time.

In all of baseball history, there have been just 44 seasons in which one member of the club was even active. As for multiple members, there have been just 17 seasons:

We just happen to be living in one of the more populous seasons for their membership. Also, the Cubs happened to sour on Sosa at the same time that the O's need a marquee name to deter fans from rooting for the newly relocated Nationals. That's the confluence of quite a number of events that was required to bring about the first two teammates who were members of the 500-HR club. And we still have spring training to get through before it actually comes to pass.