This series would mark Casey McGehee's return to face the Miami Marlins if not for the astounding production of Matt Duffy. Duffy has supplanted McGehee as the San Francisco Giants' starting third baseman and is wielding a hot bat heading into Tuesday night's opener of a three-game set. McGehee was acquired in the offseason from Miami but his struggles and the rise of Duffy forced San Francisco to designate him for assignment May 24 before the veteran accepted a stint in the minor leagues.