Jarrod Saltalamacchia of the Braves sets the record for the longest name in major league history. 15 prior players have had 13 letters in their last names, with the record having stood since the 19th Century. Saltalamacchia debuts on his 22nd birthday and gets the appearance due to injuries to Brian McCann and Brayan Pena a day earlier, both hit by bats.

On May 2, 2007 — Jarrod Saltalamacchia of the Braves sets the record for the longest name in major league history. 15 prior players have had 13 letters in their last names, with the record having stood since the 19th Century. Saltalamacchia debuts on his 22nd birthday and gets the appearance due to injuries to Brian McCann and Brayan Pena a day earlier, both hit by bats.

Source:
Baseball Reference May 2