SCOTTSDALE, Ariz. -- D-backs right-hander Zack Greinke threw to hitters Friday as part of a 40-pitch work day under rainy conditions.

“Everything felt good, went good,” Greinke said.

The hitters didn’t swing against Greinke because of the rain, and the purpose was more for Greinke to get his work in with a batter standing in the box.

Greinke said he wasn’t sure when he was pitching again next, but he said it would likely be in a Cactus League game and that after that outing, he will likely throw every fifth day during the spring.

Scratch that

Matt Koch had been slated to start Saturday’s Cactus League opener against the Rockies (1:10 p.m. MST), but his first game action will be pushed back.

Nick Green, a Rule 5 pick out of the Yankees organization, will get the start instead.

“Matt was slow to recover from his live [batting-practice] session and just has some general arm fatigue,” D-backs manager Torey Lovullo said. “At this point right now, it just made no sense to me, [pitching coach] Mike Butcher and the medical team to force things.”

Koch and Green are both part of a large competition for the final two spots in the bullpen.

Speaking of the opener

One of the big storylines of the spring is Ketel Marte’s transition from second base/shortstop to the outfield.

Lovullo said he believes it’s best for Marte to get settled in the infield this spring before he appears in the outfield during a game.

With that in mind, Marte will start at second base against the Rockies on Saturday and will likely start playing center about a week or so into games.

“I just felt like to give him every opportunity to get back into the swing of it and feel comfortable, that was going to be the best spot,” Lovullo said. “At some point, you’re going to see him rotate to the outfield."