Career
O'Brien got a late start in professional baseball. However, as a spitballer, he did have tremendous success for a few years. In 1910, when he was 28 years old, he went 20–10 for Hartford of the Connecticut State League.
In 1911, he was 26–7 for the Western League's Denver Grizzlies, leading the league in winning percentage and strikeouts. In September of that year, O'Brien made his major league debut with the Red Sox and went 5–1 with a 0.38 earned run average. The next season, he was in the starting rotation, including the first game ever played at Fenway Park on April 20, 1912.
O'Brien started Game 3 of the 1912 World Series against the New York Giants, but lost. Boston eventually took a 3–1 series lead, with ace pitcher Smokey Joe Wood slated to start Game 6. However, club owner Jimmy McAleer wanted the series to go back to Boston so he could get the gate receipts.
He ordered manager Jake Stahl to start O'Brien instead of Wood. Buck, not knowing that he was going to pitch, was hungover the day of the game. He gave up three earned runs in the first inning, and Boston lost.
Despite this, the Red Sox ended up defeating the Giants. By the next season, hitters seemed to have O'Brien's spitball figured out. He went 4–9 before being sold to the White Sox, and just one year after winning 20 games, his major league career ended.
O'Brien died in Boston at age 77.
