PHOENIX -- It was just what the Brewers didn’t need as they entered a critical closing month: Christian Yelich in the athletic training room. 

After scalding the baseball throughout the team’s just-completed homestand and after making a couple of nice running catches in the opening innings of Thursday’s series opener at Chase Field, Yelich sat out the final five innings with neck discomfort while the rest of the Brewers were limited to four singles in a 5-0 loss to the D-backs at Chase Field.

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"He just irritated his neck on one of the swings in that second at-bat. We're day to day,” Brewers manager Craig Counsell said. “I think there's a chance he misses a couple of days, but I wouldn't worry about it past that."

Here’s the problem: The Brewers can ill afford losing productive players as they attempt a late-season surge into postseason position with 130 games down and only 32 to go. Thursday offered an opportunity to gain ground not only on the Cardinals in the National League Central standings, but also the Phillies and Padres in the NL Wild Card chase on a day all of those teams were idle.

Instead, Milwaukee fell 6 1/2 games back of surging St. Louis, 3 1/2 games back of the Phillies and three games back of the Padres.

One-fifth of the regular season remains.

“To me, it felt like it was a little flat tonight, for whatever reason,” said Brewers starter Brandon Woodruff after absorbing the loss. “We’re going to have to come out and play better baseball. That’s all it comes down to.”

Energy was just the start of the issues.

• Brewers hitters were shut out for the 11th time this season on four singles and no walks against Arizona starter Merrill Kelly and reliever Caleb Smith. Milwaukee put one runner in scoring position all night; Jace Peterson singled and went to second base on a groundout in the fifth that started a streak of 14 up, 14 down to finish the game.

• Woodruff, meanwhile, surrendered five runs on eight hits in 5 2/3 innings, with all of the runs and six of the hits coming with two outs. It marked the first time since May 9 that Woodruff surrendered more than three earned runs, ending a stretch in which he’d compiled a 2.36 ERA in 14 Major League starts.

• The early exit for Yelich, who was coming off a 9-for-25 homestand against the Cubs and Pirates in which he homered twice and consistently hit the baseball hard on a line (93.2 mph average exit velocity). He isn’t producing runs at his previous clip, but Yelich has evolved into a high-quality leadoff hitter for the Brewers, batting in that spot for 67 of his last 68 starts with an on-base percentage north of .390 from that position.

Yelich leads the team in games (125), runs (83), hits (121), walks (71) and stolen bases (16), by virtue of avoiding the sort of injuries, mostly related to his lower back, that dogged him last year.

“I was talking about this when I got hurt, you have these long plane rides and you get a stiff neck and you don’t want it to get any worse,” right fielder Hunter Renfroe said. “So it’s best to have a day or two and let him get better and come back.”

Said Woodruff: “Hopefully it’s not a long absence because he’s our leadoff guy, he’s our guy to get on base.”

Yelich grounded out and struck out looking in his two at-bats against D-backs right-hander Kelly, who worked seven scoreless innings with no walks and seven strikeouts to lower his ERA through 27 starts to 2.84.

“He’s very good at what he does,” Renfroe said. “He has three pitches he can throw for strikes, and they basically are the exact same pitch that goes three different ways. You have to pick one and hope you hit it. You have to try to get him over the plate, get him up and try to do damage on it.”

Did Renfroe agree that the Brewers were flat Thursday?

“I think we could have done a better job of the approaches we took at the plate, if that answers your question,” he said after going 1-for-3. “I think some didn’t really understand the challenge ahead of us about facing him. They’d never really faced him. A lot of kids had never faced him before and didn’t really know.”

More challenges are ahead.

“We’ve gotta go,” Renfroe said. “We have to play, we have to get going, we have to win. I don’t think we played bad today, I just don’t think we took the right approach.”