Robert Allen O'Brien (born April 23, 1949 in Pittsburgh, Pennsylvania) is a former pitcher in Major League Baseball. He pitched in 14 games for the Los Angeles Dodgers during the 1971 season, including four starts and one shutout.

He played college ball at three different schools, Fresno City College, Texas A&M University and the University of Arizona and was drafted 4 times, by the Detroit Tigers in the 1968 January Draft, by the San Diego Padres in the 1968 June Draft and by the Dodgers in the 1969 January Draft and 1969 June Draft.

The Dodgers traded him to the Baltimore Orioles on December 2, 1971, (along with Doyle Alexander, Sergio Robles and Royle Stillman) for Pete Richert and Frank Robinson.

He is now a math teacher.

[ Source: Wikipedia ]