GLENDALE -- Dodgers pitcher Zack Greinke played catch off flat ground with trainer Stan Conte on Friday, and the team remains hopeful he can overcome his right calf strain to throw his scheduled bullpen session on Saturday.

Greinke suffered a mild strain of his right calf on Thursday and left his start against the Diamondbacks after just four pitches.

"He came in pretty good today. He's getting treatment today, still with the possibility of throwing his bullpen tomorrow," manager Don Mattingly said on Friday morning. "You'll see him walking fairly normally. When he starts to push, he'll feel a little something."

If all goes well, Greinke will throw a scheduled bullpen session on Saturday, keeping him on schedule to start again on Tuesday against the Mariners at Camelback Ranch. But even if Greinke remains on schedule he will only make three starts in the Cactus League, which could affect his availability for pitching one of the two regular season games in Australia.

Mattingly said the normal plan would have been for his starters in Australia to throw roughly 90 pitches, but Greinke's arm might not be built up enough by March 22-23.

"It may affect if Zack's able to go [to Australia]," Mattingly said. "Obviously his pitch count is not going to be built the same. It could end up being a different pitch count kind of start, though that's down the road."