Pereira was scratched from Friday's Cactus League lineup against the Cubs with tightness in his right side, Scott Merkin of MLB.com reports.
Pereira should be considered day-to-day. The 24-year-old outfielder was acquired from the Rays back in November. He's appeared in 50 career big-league games, slashing .146/.227/.215 across 176 plate appearances.