Why is Justin Upton struggling?

Arizona Diamondbacks All-Star right fielder Justin Upton is marred in a month long slump.

Upton’s average has dropped from .300 on July 1st to .281 on July 19th. His OPS has gone from .892 to .847 in the same timeframe.

In June Upton was incredible and he is following it up with his worst month of the season. The question is why?

The drop in Upton’s on-base % (OBP), which accounts for part of the formula in OPS, is easy to account for. He isn’t putting the ball in play as much in July. Upton’s K% is 25.4% in July, compared to 14.2% in June.

The other number that really jumps out at you is Upton’s BABIP (Batting Average on Balls In Play), which was .440 in June and is .162 in July.

Upton, historically, has a high BABIP. In 2009 it was .360 and in 2010 .354, but .440 for an entire month is a bit ridiculous. With that said, something is up with the .162 number in July. No question part of it is getting unlucky, but there is more to the issue.

Upton has stopped driving the ball in July.

His line drive % (LD%) in June was 22.1% (Career LD% 19.1). In the month of July Upton’s LD% is 12.8%. He had nine doubles in June in 102 at bats, while in July Upton has only 2 doubles in 54 at bats. Upton is on track for about half as many doubles in July as he had the previous month.

Upton’s ground ball % has also decreased from 39.5% in June to 35.9% in July.

Which leaves us only one place for all the extra balls in play to go: up in the air.

Upton’s fly ball % has increased from 38.4% in June to 51.3% in July. This would be ok if Upton’s home run/fly ball rate increased dramatically with all the extra fly balls, but it has only increased by 4%.

This all leads to the conclusion that Upton is slumping because he is hitting lazy fly balls to the outfield (he hasn’t had one infield pop out the entire month) and striking out too much.

The important part is Upton snaps out of his slump. It is unrealistic to ask Upton to have another month like June, but the Diamondbacks need him to step it back up if they really want to make a run at the San Francisco Giants.

Thank you to Fangraphs.com for the statistics used in this story.

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