- Card series: Beginnings: 1880's
- City: Brooklyn
- Team: Bridegrooms
- League: American Association
William D. O’Brien (1863-1893) was an outfielder for the NY Metropolitans in his rookie year, 1887, and then played five years with the Brooklyn Bridegrooms. A speedster, O’Brien stole 321 bases in his illness-shortened career, hitting .282 with an OBP of .344. One of those with the distinction of playing for Brooklyn’s pennant winners in the AA in ’89 and NL in 1890.
- Ill when he reported for spring training in ’93, team raised money and sent him to CO to heal
- The weakened O’Brien succumbed to typhoid fever at the age of 29