Joc Pederson was an 11th round pick back in 2010, and once he was promoted to the Solar Sox in 2012, his name was synonymous with the phrase "can't miss prospect". His ISO and wRC+ got better with each level he climbed, and despite a rough introduction to the big leagues at the tail end of 2014, his 2015 season has been fantastic, at least overall.
His strikeout rate is high, but other than that all of his other statistics are above average. His BB% borders on what FanGraphs considers to be excellent, and his ISO of .234 places him in the top 20 of MLB. For a 23-year-old rookie, with under 500 plate appearances in the majors, he has an undeniably bright future. However, since the calendar turned from June to July, Pederson hasn't been the same.
For the first three months of the season, Pederson was undoubtedly elite. His ISO compared favorably to Paul Goldschmidt; his wOBA to Albert Pujols; and his wRC+ to Josh Donaldson. In the month of July, he's closer to a trio of Freddy Galvis, Mike Zunino, and Omar Infante.
One of the first places to look when a player is experiencing such a notable dropoff in production is his zone profile. You can observe differences in where a batter is being pitched, whiff rate, and various batted ball outcomes; for Pederson, it's his swing rate that seems to be causing him some trouble.
Since the start of July, there has been a clear difference in Pederson's swing tendencies. From April through June, he had a remarkable eye and mainly swung at pitches within the strike zone. He had a tendency to swing at the middle-outside pitch, as well as directly below the zone, but other than that Pederson didn't seem to chase pitches.
While the sample is much smaller in July, it's obvious that Pederson is not as disciplined as he was earlier in the season. It's also clear that he's not as aggressive on pitches in the zone. In the 3x3 quadrant that represents the strike zone, Pederson's swing rate has dropped in seven out of the nine boxes. Overall, he's letting pitches go by that he shouldn't and swinging at those that he should leave alone.
While these changes help explain Pederson's recent struggles, there's another factor at play that's contributing to his decreased production, his exit velocity.
For most of the season, Pederson's exit velocity has been above the major league average, but over the last two months he's experienced a significant amount of variation. He's dipped below the MLB average a few times, and he's in the midst of his worst stretch of 2015; FanGraphs is in complete agreement with the graph above. Pederson's ground ball rate has increased considerably, and his hard-hit percentage is way down.
Unfortunately for Pederson, all of these statistics are trending in the wrong direction. His LD and FB percentages have decreased, while his GB rate has increased by 24.8 percent in the last month. His medium hit balls haven't changed too much, but Pederson has seen his percentage of softly hit balls skyrocket by 100.77 percent, and his hard hit ball percent plunge by 38.25 percent.
Regardless of which statistics are looked at, they all come to the conclusion that Pederson is going through some incredible struggles. Even his pitch values have shown a clear difference between the first three months of his season and the past 30 days. It seems unlikely that the Dodgers would send him back to the minor leagues to figure things out, but if he can't get back on track, it's something that they might seriously have to consider. By wRC+, Pederson's been 62 percent worse than the average major league hitter in July, and that can't continue for a team with serious playoff hopes.