Loretta's playing career spanned 15 big league seasons. He played with the Padres from 2003-05. Loretta most recently was with the Los Angeles Dodgers.
The two-time All-Star played with the Red Sox in 2006, when new Padres general manager Jed Hoyer was in Boston's front office.
"It was clear to me that he could have a great impact on an organization in a front-office role once he finished his playing career," Hoyer said. "I feel fortunate that the timing of my arrival in San Diego and Mark's retirement coincided and I was eager to bring Mark on board to help in all aspects of the department."
Loretta, who played mostly at second base during his career, also played for Milwaukee and Houston. A two-time All-Star, Loretta finished his career with a .295 batting average with a .360 on-base percentage. His best season came in 2004 for the Padres when he set career highs in batting average (.335), homers (16) and RBIs (76).
Information from The Associated Press was used in this report.