Olivera, signed to a $62.5 million contract in May, was injured Saturday night while running to first base and was placed on the DL retroactive to Sunday. He was sent to the club's training center in Arizona for rehabilitation.
Olivera, 30, was seven games into a stint at Triple-A Oklahoma City after playing six games for Double-A Tulsa. He's been playing third base and second base. He has hit a combined .358 with two homers and seven RBIs, and a .968 OPS.
Mattingly said he had no timetable for Olivera's return to action.
"They're calling it slight. I'm assuming it'll be fairly short," Mattingly said. "We never had a true timetable [to call him up to the big leagues]. But less time playing obviously changes it a bit."
• Dodgers relievers Paco Rodriguez and Pedro Baez moved closer to rejoining the big league club as they continued injury rehab assignments with Oklahoma City on Tuesday night.
Rodriguez (elbow bone spur) needed only six pitches for a perfect inning that included a strikeout in his fourth appearance.
Baez (strained pectoral muscle) also threw a perfect inning, with two flyouts and a groundout in his third appearance.
Ken Gurnick is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.