He hit 19 homers a year ago - more than any Padres player hit - with 62 RBI's in 113 games. He batted .251 with a .326 OBP.
He had considered joining an AL team as a designated hitter, but instead will return to the West Coast for the first time since the Los Angeles Dodgers traded him to the Florida Marlins in 1998.
Piazza's numbers have declined over the last few years, not topping 20 homers since 2002. From 1995 through 2002 he averaged over 30 homers and 100 RBI's.
Piazza has always been below average behind the plate but he is expected to stay behind the plate for 75-100 games with San Diego.