Greinke (groin) is scheduled to throw a bullpen session Sunday, Zach Buchanan of The Athletic Arizona reports.
Greinke is currently dealing with a bout of groin tightness that he picked up during his previous spring start. While the issue isn't thought to be anything overly serious, it's expected to push his next start back by a little bit, which would make pitching on Opening Day unlikely. Barring any setbacks in his bullpen Sunday, Greinke could be cleared to return to game action shortly thereafter. A clearer timetable for the veteran should emerge once he returns to Cactus League action, but as it stands now, he's loosely lined up to pitch one of the games during the first week of the season.