The team optioned pitchers Simon Castro, Jeremy Hefner, Evan Scribner, Aaron Poreda and catcher Luis Martinez to Triple-A Tucson.
The Padres also optioned infielder Jeudy Valdez to Class A Lake Elsinore.
The Padres reassigned pitcher Anthony Bass, infielders James Darnell, Anthony Rizzo, Andy Parrino and catcher Jason Hagerty to Minor League camp.
"As you move into March, you have to thin the room and move guys to the other side [to Minor League camp]," said Padres manager Bud Black.
All of the players will still be able to appear in Cactus League games and many will, like Rizzo, a first baseman who is off to a hot start this spring. Rizzo had four hits and two stolen bases in a victory Thursday against the Dodgers.
Rizzo is second on the team with eight hits and is hitting .444 with three doubles and four RBIs. Rizzo was one of four players obtained in the December deal with the Red Sox that saw the Padres send Adrian Gonzalez to Boston.
"He came in as advertised, on the baseball field and as far as his makeup and work ethic," Black said.
Minor League games with other Cactus League teams begin on March 18.