LOS ANGELES -- For now, John Ryan Murphy will be behind the plate for the D-backs when ace Zack Greinke starts.

“I thought the times they worked together in Spring Training they were in rhythm,” D-backs manager Torey Lovullo said. “John Ryan was receiving the ball very, very well. I watched their interactions very carefully. It looked like there was a great deal of comfort between the two of them. I would see John Ryan sitting with Zack often. Those weren’t the only reasons. I think when you add them all up, they give you the best signal possible that this could be a good starting point.”

Veteran Jeff Mathis was behind the plate for all 33 of Greinke’s starts last year, but he signed with the Rangers during the offseason.

Lovullo had said early in Spring Training that he hoped to find one guy to pair with Greinke this year, because he believed that was what was most comfortable for the 35-year-old.

Murphy, Alex Avila, Carson Kelly and Caleb Jacobs -- who was optioned to Triple-A Reno -- each had a chance to catch Greinke this spring, and the right-hander told Lovullo that he felt comfortable with any of them.

Greinke also told reporters he was open to throwing to different catchers if Lovullo wanted to determine who would play based on matchups.

“I got as much input as I possibly could from Zack,” Lovullo said. “He was very neutral, believe it or not. He felt like he didn’t want to pick one over the other. I had a lot of conversation with him. I got a lot of input from a lot of different areas besides Zack. There could be adjustments. There could be some things that could change. For right now, I made the decision that’s the way I want it to go.”

Happy birthday, indeed

Christian Walker got quite the 28th birthday gift when he walked into the visitor’s clubhouse Thursday morning and saw his name in the starting lineup at first base.

The right-handed hitter got the start against Dodgers lefty Hyun-Jin Ryu, his first Opening Day in the big leagues, and he responded by hitting a seventh-inning homer in the D-backs' 12-5 loss.

The left-handed-hitting Jake Lamb still projects to get most of the playing time at first base.

“As I’ve been saying, this isn’t going to be a straight platoon situation for that,” Lovullo said. “But I feel like it’s a way to get Christian a start. We face a lot of righties coming up in the next several days. Jake will obviously get those starts. Will it be a platoon situation? Not at all. Jake is going to get a number of starts against left-handed pitchers.”