Alex Rodriguez turns 30 today. It's a good point to look at his career and see how he's doing vs. the all-time greats. A-Rod has more home runs at age 30 than any other player. But it's more useful to look in terms of full seasons.

Seasonal age is the age a player is for most of the baseball season. The cut off is July 1. Whatever age you are before July 1 is your age for the year. By this measure, Alex is only 29. By seasonal age, here are the most home runs through age 29:

A-Rod and Vlad will continue to add to these totals this year, and Andruw Jones gets next year as well. That means that A-Rod is likely to have a 20 to 30 home run lead on Griffey at the end of the season. If Alex can end the season with 430 home runs, he'll have 11 more seasons to bring him through seasonal age 40. He'll have to average 30 home runs a season to break Aaron's record. Not easy, but certainly not impossible. Still when you look at the names on the list, it's amazing how many were ahead of Ruth at the same age and never caught the Babe.

Correction: I meant 30, not 33.