Miguel Montero came to bat in the bottom of the ninth inning the game tied at 3.

He took the first pitch for a ball and then swung mightily at the next three pitches never making contact.

“Those are the swings we’ve seen far too often this year” a Diamondbacks broadcaster said.

Mention the criticism to Montero and he shakes his head. He knows he’s had a lousy year offensively. He knows his lack of production is in part why Arizona ranks 12th in the National League in home runs and 11th in slugging percentage. He’ll even admit to having “no clue” at the plate for much of the season.

But the idea that he’s overswinging?

“That’s the only thing that’s really bothered me” Montero said. “Everything is easy from the outside. Everybody say ‘Why did he swing at that pitch? Why did he swing so hard?’ I don’t pay attention to that anymore because it can get you crazy.”

By any measurement Montero has regressed offensively after back-to-back productive seasons in 2011 and 2012. Here are a few relevant numbers:

2012: .286 batting average .391 on-base percentage .438 slugging percentage 88 RBIs 73 walks .259 average against left-handed pitchers.

2013: .233 batting average .313 on-base percentage .349 slugging percentage 38 RBIs 42 walks .194 average against left-handed pitchers.

The numbers tell only part of the story though. What’s missing is the why. What happened to the hitter who had at least 15 homers and 86 RBIs each of the past two seasons and had a Wins Above Replacement (WAR) of at least 3.9?

(Montero’s WAR this year is 0.7)

Baseball’s advanced metrics offer a few clues. Montero is hitting more ground balls 45.9 percent to 43 percent in 2012 which likely is a factor in his batting average on balls in play being significantly lower (.286 to .333). Also he hasn’t been as disciplined at the plate swinging at 32 percent of pitches outside the strike zone compared with 29.8 percent last year. And when he does swing at those pitches he’s making contact less frequently 62.1 percent of the time this year compared to 65.6 percent in ’12.