Former Rangers general manager Dan O'Brien, Sr. passes away at age 87

Dan O'Brien, Sr., who spent over 45 years as a professional baseball executive, passed away on Monday in Dallas at the age of 87.
Mr. O'Brien served as the second General Manager in Texas Rangers history, replacing Joe Burke with the title of Vice President in September 1973. His title was changed to General Manager the following year and he held that position until January 1979, sharing the duties with Eddie Robinson in the last two seasons. He oversaw Texas' 27-win improvement from the 1973 to 1974 seasons and was with the club during its 94-victory campaign in 1977, a team record that was not eclipsed until 1999.   
He began his baseball career in 1955 as a minor league general manager and spent ten years with the National Association before joining the Rangers. He left Texas to become President and later General Manager of the Seattle Mariners. Mr. O'Brien also held front office positions with the Cleveland Indians, California Angels, Arizona Fall League, and USA Baseball before his retirement in 2000.
His son, Dan. Jr. is also a longtime MLB front office executive and served as the Rangers Assistant General Manager from 1996-2003. Mr. O'Brien is also survived by his wife, Mary Ann and daughter Lori.
Services for Mr. O'Brien are pending.