Greinke has dealt with a tender elbow all month and has been throwing on flat ground instead of having regular bullpen sessions.
Mattingly gave no indication about who will replace Greinke if he misses the start.
"Nothing to talk about right now," Mattingly said to MLB.com. "We'll let you know more [Wednesday]."
Greinke has lost two of last three starts.
Greinke, 30, is 12-8 with a 2.75 ERA and 170 strikeouts this season for the Dodgers, who lead the National League West by 4.5 games over the San Francisco Giants.
- Scooby Axson