Is a Bad Neck Behind Butler's Power Outage?

Billy Butler has been having an off season by his standards. His batting average and power are at the lowest levels since 2008. He just has not been the same batter. Last week, the 27-year-old rested a couple of days because of a "mysterious" neck injury. The neck injury may be behind part of his struggles this season.

The neck injury came to light just this past week. According to Butler:

"I can't really tell you anything. It's not from anything, it's just not moving very well. I couldn't quite get turned to the pitcher last night. It's not feeling very good."

Even by watching him with my untrained eye this season, something seemed off.

The injury materialized out of no where, but I had an idea he maybe dealing with a problem a couple of months ago. At FanGraphs, I created a metric, HURT, which looks for players with similar traits as players who were injured and played through those pains (loss of power, speed and contact). Billy Butler's name showed up on the list. While he was not at the level of hitters who are almost 100% likely to be hurt, he was in the top 20. At the time, he was not linked to any injury.

Butter's production is off in several categories leading to the high HURT score, but the main cause was his low power. Here are his isolated powers values (ISO or SLG-AVG) over the past few seasons:

Season: ISO
2007: .155
2008: .124
2009: .191
2010: .151
2011: .169
2012: .197
2013: .124

It is at a 5 year low (and ties the 2008 value).

The drop in ISO can be contributed to him just not hitting the ball as far. Here are the batted ball distances for the balls he put into play over the past seven seasons (source).

2007: 191 ft
2008: 186 ft
2009: 200 ft
2010: 192 ft
2011: 197 ft
2012: 194 ft
2013: 182 ft

Every batted ball on average is going 10 to 15 feet less in 2013 compared to recent seasons. Most players see their power peak at age 27, not drop off significantly.

So can a direct link be be established between the power drop and injury? No, not at all. He could be aging to the point that his one skill set, hitting for decent power, drops off rapidly. Pitchers and fielders may be adjusting to his hitting pattern. His gut could be getting in the way of swing plain. Nothing can be known for sure.

With the exceptions said, some warning signs exist pointing to his drop in production being injury related. He is dealing with an injury which allows him to play some games and not others. His power is off at a point in his career when it should be at its highest. I think he is hurt a bit, but not enough to keep him out of the lineup. A Billy Butler at 75% is better than the 100% healthy options (Johnson, Kottaras, Maxwell, etc) on the Royals bench.

Billy Butler's season has been a little disappointing. The main cause for his decline has been a drop in power output. A neck injury may be behind the decline. It would be nice to see him get back to 2010 to 2012 levels of production as the Royals make a run at the playoffs for the first time since 2003.