letters (not mail)
As unlikely as it may sound, you might one day be on Wheel of Fortune, and it's possible that the category will be "Pitchers who hit Craig Biggio with a pitch". Then you'll be glad you read this. Otherwise... well... at least it's something to read that isn't about some "fancy football player".
The most commonly used letter in the spelling of the names of pitcher who have hit Craig Biggio with a pitch is E. 239 Es go into the spelling of the first and last names of the 211 pitchers who have plunked Biggio. Next behind them is the letter A with 223, and the letter R with 210. 151 of the 211 pitchers in the group have at least one E and 151 have at least one A, but only 102 have both an A and an E. 144 pitcher who have plunked Biggio have an R in there name, and 128 have an N.
No pitcher with the same letter repeated more than 4 times in their first and last name has ever plunked Biggio, and Biggio has never been hit by a pitcher with as many Gs in his name as there are in "Craig Biggio". He has been hit by 4 pitchers with as many uses of the letter 'I' in his name as there are in Craig Biggio, but never by a pitcher with 4 I. (Pitchers with glasses are another story).
X and Q are the most infrequently used letters in the names of pitchers who have hit Biggio with a pitch. Only Greg Maddux and Xavier Hernandez have use X, and only Joaquin Benoit and Jason Marquis have a Q.
Garrett Stephenson has the most total letters among plunkers of Biggio, but Kyle Farnsworth's name has the most different letters (13). Jamey Wright has the longest name in the group that doesn't use any letter more than once (11 letters), and Bill Pulsipher is the only pitcher to throw one of Biggio's 281 HBPs to use the letters H, B and P in his name.
As far as Wheel of Fortune strategy goes, be sure to start with R and N - but if there are no Rs, go with S - among pitchers who don't have an R in their name, S is the most commonly used consonant. 70% of pitchers who plunked Biggio who don't have an R in their name have an S but only 66% without an R have an N.
Here's a handy chart of letter usage in the names of pitchers who have plunked Biggio: