Early last season, I did a piece highlighting Matt Kemp’s fast start. Coming off a near-MVP season in 2011 when he flirted with the Triple Crown with a .324/.399/.586 slash and league-leading HR (39) and RBI (126) totals, Kemp kept right on rolling, going 2 for 5 on opening day and maintaining that .400 batting average for all but 3 of his first 30 games. Kemp’s April looked like .417/.490/.893 with 12 home runs.

Kemp would go down with an injury in mid-May, and then re-injured himself in his second game back at the end of that month. Returning after the All-Star break, he finished just .280/.331/.461 with 11 home runs over his last 70 games.

For 2013, the power circuits are off for Kemp, with just two home runs on the season and a .251/.305/.335 slash before he injured his hamstring a couple of weeks ago. After the jump, I’ll take a closer look at Kemp’s decline and what might be causing his struggles.

For some context, only 18 players have had 12 home runs through their teams’ first 25 games (Kemp did it in 23 games), and none of them did it more than once.  Here are those players, showing how their seasons turned out.

Eric Davis and Mark McGwire are the only ones to miss significant time due to injury, though not to the same extent as Kemp. McGwire had no drop-off in performance after his return from a 3-week DL stint, while Davis missed a handful of games at several points during the season, so difficult to gauge what effect injuries may have had on his performance.

For the rest who stayed healthy, mostly outstanding or even historic seasons, as evidenced by the abundance of black ink. The verdict – a blistering start is not a fluke; only very good players having outstanding years will start that hot.

But, were those seasons one-offs and should we therefore not be surprised by Kemp’s struggles this year? Here’s how the same players did in the seasons following the ones above.

More evidence that the preceding seasons were not flukes. Less black ink but only Keltner (whose pedigree is probably a notch or two lower than the other players in this group) and Campanella had fall-offs of the magnitude that Kemp is currently experiencing. That being the case, is Kemp similarly of a lesser pedigree or is his injury still affecting his play (or, perhaps, a bit of both)?

Comparing this season to Kemp’s near-MVP campaign in 2011, his walks are down (10.7% of PAs then, 6.7% now) and strikeouts are up (23.1% then, 28.6% now). Those numbers are consistent with his pitch-count data showing a reduction in 3-ball counts from 20.6% of PAs in 2011 to just 15.7% in 2013.

More strikeouts and fewer walks usually means less patience at the plate, a conclusion borne out in the 2013 data below.

Data provided by FanGraphs.com

Let’s see what can be gleaned from the above:

• Kemp is seeing about the same proportion of pitches in the strike zone as his teammates and MLB as a whole.
• He is also fouling off a similar percentage of pitches. But, his rate of swinging strikes is way out of whack – about 85% higher than his teammates and almost 70% higher than MLB overall.
• Those extra swinging strikes are the result of offering at about 9% more of the pitches he sees, compared to his teammates. That 9% breaks out as as a 6% higher swing rate on pitches in the zone, but a 15% higher swing rate on pitches outside the zone.
• The end result are the bolded numbers, indicating that Kemp is making contact only two-thirds of the times that he swings, compared to an MLB average of almost 80%. When he swings at pitches in the zone, his contact rate is about 8% lower than the MLB average, but almost 35% lower when he swings at pitches outside the zone.

To put those numbers into perspective, only 6 players this season (min. 150 PA) have a lower overall contact rate than Kemp, and only 4 have a lower contact rate when offering at pitches out of the strike zone.

How do the above plate discipline numbers compare to Kemp’s recent past?

Data provided by FanGraphs.com

Surprisingly, very little difference in Kemp’s tendencies in recent seasons. Kemp has been just as much the free swinger then as now. The difference is contact on swings outside the zone – it was happening before, but not nearly as much now.

One other note on Kemp: he has benefited from an unusually good BABIP, with a .352 mark for his career. Even with his troubles this season, his BABIP was still a healthy .348 indicating that when he makes contact, he does so solidly.

Hopefully for Kemp, he can make a fresh start when he returns from his injury. More patience at the plate should lead to better swings, more contact and a return to the form he exhibited in 2011 and the start of 2012.