Van Slyke, healing from a strained mid-back muscle, went 1-for-4 with a double and strikeout as a designated hitter against Stockton in his first rehab game.
Peralta, healing from a pinched nerve in his neck, reached his pitch limit after two-thirds of an inning, charged with one run on two hits in his second rehab appearance.
The list of Dodgers lined up for injury rehab assignments with Rancho Cucamonga in the next few days includes Paco Rodriguez (elbow spur), who shows up there Monday, Brandon Beachy (Tommy John surgery) on Tuesday, and Brandon League (right shoulder impingement), who goes back to back both of those days.
"Pretty good team down there," the Dodgers manager said.
Peralta, League and Rodriguez could provide needed reinforcements to a bullpen that has wobbled much of the year.
Mattingly said Peralta is the closest to returning, League most likely the furthest, because he really didn't have much of a Spring Training.
The Dodgers currently have nine players on the disabled list.