Jed Hoyer will be named the San Diego Padres general manager, a baseball source confirmed to the Globe's Tony Massarotti.
The 35-year-old Hoyer, who recently held the title of vice president and assistant general manager, has been a member of the Red Sox' front office since 2002.
It is uncertain when the Padres will make a formal announcement.
Hoyer, a New Hampshire native who played baseball at Wesleyan, first gained prominence among Red Sox fans following the 2005 season, when he and Ben Cherington served as co-general managers during Epstein's 10-week hiatus after departing following a falling out with team president and chief executive officer Larry Lucchino.
During Epstein's absence, Hoyer and Cherington, along with fellow front office members Bill Lajoie and Craig Shipley, made a couple of significant transactions, including the deal that sent shortstop Hanley Ramirez and prospects to the Florida Marlins for pitcher Josh Beckett and third baseman Mike Lowell.
Hoyer's duties with the Red Sox primarily concerned major league personnel. He will replace Kevin Towers in the general manager's role in San Diego. Towers was fired earlier this month after 15 seasons in the role.
Towers has a standing offer to join the Red Sox' front office staff, the Globe's Nick Cafardo has reported. ESPN's Peter Gammons also reported today that a similar offer has been extended to former Blue Jays general manager J.P. Ricciardi, a Worcester native.