FanGraphs has a column on whether Naquin is having a breakout season or not. Here's the conclusion...
Naquin’s breakout is a combination of some good fortune created by his home park and some weak opponents, but there are also some real changes in terms of his approach at the plate, as well as his approach to the swing itself that point to real improvement. It feels more than a bit aggressive to say he’ll finish the year as a top 10 offensive performer in the National League, but finishing the year as an above-average producer certainly feels well within the range of most likely possibilities.
Is this sustainable? In Naquin’s case, the answers are a bit murky.
blogs.fangraphs.com
The Great American Ballpark is statistically the best park in the league to hit in. And four of Naquin's eight homers were against the Pirates. But he's made some changes in his batting stance and his approach to hitting, specifically, swinging earlier in the count, that have helped him. And for some reason FanGraphs can't explain he's been seeing 70% fastballs. They seem to think that once pitchers stop throwing fastballs down the middle on the first pitch to Naylor his numbers will trend back to his career norms.
It he can stay healthy and stay in Cincinnati he might put up some decent production over the course of the season.