PHOENIX -- The D-backs' day started off on the wrong foot when they learned they would be without the services of left-hander Tommy Henry for at least the next couple weeks due to left elbow inflammation.

Things would only get worse as Arizona was shut out for just the second time this year, falling 4-0 to the Mariners on Sunday afternoon at Chase Field.

The D-backs are 7-16 in July, a slide that has dropped them from first place in the NL West to third place, four games behind the first-place Dodgers and two games behind the second-place Giants.

The club was headed to San Francisco after the game, where it will open a four-game series at Oracle Park on Monday.

Henry had been pitching well for the D-backs, but he’s the second starting pitcher to go on the injured list in the past two weeks, joining Zach Davies. Henry felt some discomfort in his elbow during his start on Friday night. The good news is an MRI showed no structural damage in the elbow, but there was inflammation that will take some time to get rid of.

“Thankfully, of all the scenarios that it could be, it's probably one of the better-case scenarios,” Henry said. “It was nothing that really fell out of the ordinary, but in the last outing, as the game progressed, [it] just really started to bother me. [It was] enough to where I felt like I had to speak up afterward, which was unfortunate. It's tough because you compete and you feel like you're able to get the job done, but just long term, it wasn't a recipe for success.”

The D-backs filled Davies' spot in the rotation by calling up right-hander Brandon Pfaadt from Triple-A Reno. What they do to fill Henry’s spot remains to be seen.

For now, Ryne Nelson and Zac Gallen will take their regular turns in the first two games of the San Francisco series, and Pfaadt will start Thursday's finale. As for Henry’s spot on Wednesday, Arizona could once again promote someone from Reno. Slade Cecconi and Bryce Jarvis would seem to be among the candidates.

“I think anytime one of your five starters goes down, and the way Tommy has been throwing the ball and keeping us in ballgames, that's a concern,” manager Torey Lovullo said. “It's a concern, but it's also a time for somebody to step up and get an opportunity and get the baseball in their hands and go out and execute and help us win baseball games.”

The D-backs fell behind early Sunday as Merrill Kelly struggled to find his command in the first, allowing a pair of runs thanks, in part, to two walks, one of which came with the bases loaded. He threw a whopping 41 pitches.

But while it was not an ideal start, Kelly found a way to somehow settle in and make it through five innings.

The Mariners did not do much after the first two innings, but Arizona's offense did even less, collecting just three hits on the day.

When it was over, the D-backs had already turned the page, looking toward the next challenge.

“It sucks to have guys get hurt, for sure, but [it's] also a part of the game,” first baseman Christian Walker said. “Just hope for the best, and obviously, a quick recovery for both of those guys. But I mean, you don't really have time to dwell on what you think is happening or happened. It's about tomorrow. Turn the page, you know, flush it -- whatever cliche you like -- but we’ve got four games in San Fran and we've got to win most of them.”