SAN DIEGO – Twice in the early innings on Thursday night, a Padres hitter scorched a ball to left field, and twice the Diamondbacks’ David Peralta raced to make a play, the first ball taking him into the gap, the second one back toward the wall.

Neither play was especially breathtaking, nor were they pivotal to the Diamondbacks’ victory. But they served as reminders of something that has changed this season: The expectations around Peralta’s defense have shifted significantly, to the point that catches like those are almost commonplace. He is expected to make them.

Peralta has never been a poor defender, certainly never to the levels of Yasmany Tomas or other rough-around-the-edges corner outfielders the Diamondbacks have employed in recent years.

But he’s never been able to make consistently challenging plays as frequently as he has this year. Outfield coach Dave McKay sees a few reasons for this. For one, Peralta is playing almost exclusively in left field rather than bouncing between there and right field.

While the two positions don’t seem that different, McKay says they can be, particularly when it comes to the different angles the ball takes off the bat from left- and right-handed hitters. And, McKay said, just as Peralta was beginning to get the hang of right field, the Diamondbacks traded for J.D. Martinez midway through last season, necessitating a full-time move to left.

While Peralta was playing right, McKay said he had him change the way he sets up before the pitch, squaring his body less toward home plate and more toward second base, a small tweak that let him get better jumps on balls in the gap. In left, he’s made a mirror image of the same adjustment.

“It’s an adjustment that really helped him,” McKay said. “He’s getting more comfortable with it and it’s more of an instinctual thing instead of having to think, think, think.”

Peralta, who was not in the lineup on Friday night, was unavailable for comment because he was not at Petco Park prior to the game.

Manager Torey Lovullo was dodgy when discussing the subject on Friday afternoon. First, he said it was “just a day” for Peralta and that the matchup against Padres lefty Joey Lucchesi made it a natural day for him to sit.

But then Lovullo added that Peralta would be “back out there as soon as possible.” When asked why Peralta wasn’t at the park, Lovullo said he told him to stay at the hotel to “relax and take some time off,” adding that Peralta would be available and would arrive sometime before the game.

Peralta was not seen in the visitors’ dugout during the first inning.

As for his defensive improvement, it isn’t evident in advanced metrics, and while people around the team can’t explain that, they have little doubt he’s made significant strides since last year. Peralta has received plenty of attention for his breakout season at the plate. He might be quietly making a similar jump defensively.

“Absolutely,” McKay said.

Peralta’s background – he was signed out of Venezuela as a pitcher – lent itself to him being raw as an outfielder. But McKay thinks Peralta as improved and will continue to do so. He’s wired to work hard.

“He comes out and works at it,” McKay said. “And he works at it a lot, especially at home when we have the field (available before the game). I keep saying he’ll get better and better as long as he stays healthy.”


Reach Piecoro at (602) 444-8680 or [email protected]. Follow him on Twitter @nickpiecoro.