Tim Federowicz, obtained in the Matt Kemp deal with the Dodgers in December, is a candidate to win a spot on the roster as the backup catcher.
Nieves, who has played with seven teams over an 11-year Major League career, spent last season with the Phillies and hit .254 while appearing in 36 games.
Nieves, a native of Puerto Rico, is a career .243/.281/.317 hitter. His older brother, Melvin, played parts of three seasons for the Padres as an outfielder from 1993-95.
Wil Nieves was drafted in the 47th round in 1995 and, under the old draft-and-follow rules, didn't sign until the following May.
He arrived to the big leagues on July 21, 2002, in a game against the D-backs at Qualcomm Stadium and had one hit in three at-bats, a single off Hall of Fame pitcher Randy Johnson. Nieves also caught rookie Jake Peavy, who was making his fifth career start.
Nieves proved valuable to the D-backs in 2013, filling in for an injured Miguel Montero and hitting .297 in 195 at-bats.
Corey Brock is a reporter for MLB.com. Keep track of @FollowThePadres on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.