It's often said that the casual fan can't truly pick out the details of the game of baseball that statistics show us. The difference between a .280 batter and a .320 batter is only 1 or 2 hits a week. Similarly, Craig Biggio gets hit by a pitch once every 43.5 plate appearances on prime numbers days of the month, but he gets hit once every 43 plate appearances on non-prime days. Leaguewide, for the 1988 through 2006 seasons, batters were hit once per 126 plate appearances on prime numbered days and once per 125 plate appearances the rest of the time. That's just the sort of thing you'd never notice, even if you were diligently keep score every time you go to the ballpark.
More importantly, Biggio gets hit by pitches once per 45.4 plate appearances on prime numbered days in prime numbered months compared with once per 43.9 plate appearances the rest of the time, but the league wide splits are identical whether or not the date has a prime number for both the day and month. But, very strangely, when the date is a prime numbered day in a prime numbered month in a primed numbered year, Biggio get's hit once per 36.7 plate appearances, compared to once per 43.4 plate appearances the rest of the time.
In all, Biggio has been plunked 97 times on prime numbered days, 109 time in prime numbered months and 82 times in prime numbered years. He's been hit 35 times on prime numbered days in prime numbered months, and 29 times on prime numbered days in prime numbered years. He's been hit 25 times in prime numbered months that happened to be in prime numbered years, and 10 of those times were on prime numbered days ( in prime months in prime years). The most recent such date of an HBP:BGO was July 5, 2003.
Craig Biggio's 82 plunks in prime numbered years is 14 more than any other player in history has had in prime years. Jason Kendall is 2nd with 68. As math would have it, there have been 5 prime years in the last 20, more than any 20 year span in baseball history. Biggio is 4th all time in career hits in prime numbered years, behind Tony Gwynn, Paul Molitor, Rafael Palmeiro - and tied with BJ Surhoff (yes, BJ Surhoff). He's also 1st in doubles in prime numbered years, and 2nd in runs (behind Bonds).
Biggio has recorded all 285 of his HBPs wearing the uniform number 7, which is a prime number, but he did wear number 4 in 1988. But, he's been hit 70 times by pitchers wearing 14 different prime numbers. He's been plunked by a pitcher wearing every prime number from 17 to 71. 3 pitchers wearing prime uniform numbers have plunked Biggio on a prime numbered days in prime numbered months in prime numbered years.
The July 5, 2003 plunk mentioned above was thrown by Jeff Suppan, who was wearing prime number 37. It was Biggio's 229th career HBP (also prime) as well Suppan's 41st career hit batter (prime again). And, he did it in the 7th inning.
Once again, there was probably a point to all this. But there won't be another opportunity for anyone to get hit by a on a prime numbered day in a prime numbered month in a prime numbered year until May 2, 2011.