0

Uniform number 0 was not traditionally worn in baseball, as in most other North American professional sports, until the 1970s. It was the same for number 00. These numbers were traditionally reserved for mascots, bat boys, and for model uniforms. 0 has been worn by a few players on the field, most notably Al Oliver who sported it for various teams in the second half of his career. It had once again become discarded in the 21st century until taken up by Mallex Smith, who was one of the first to use it without having a first or last name starting with the letter "O".

Notable players who have worn this number

• Oddibe McDowell
• Kiyoyuki Nagashima (1st NPB player to wear 0, in 1983)
• Al Oliver
• Rey Ordoñez
• Junior Ortiz
• Adam Ottavino
• Mallex Smith