Billy Butler's offensive breakout, evidenced by a .306/.367/.501 line, has been one of the real bright spots for the Royals this season. Butler's been a patient hitter to go with a .300 average, and he's shown some of the power we've been waiting for. After all, the guy slugged .400 last season.

As has been noted by many, Butler's ability to post these kind of numbers in his age 23 season is a hugely positive sign, and makes him a likely bet to be a productive hitter for the next decade. Somewhat amazingly, Billy Butler has emerged as a Royals position player prospect that hasn't been a disappointment. 

While most expected Butler to hit, there have been questions about his glove from day one. When the Royals acquired Mike Jacobs last offseason, most assumed that Jacobs, one of the worst fielders, at any position, in baseball, would become the regular first baseman. Butler's defensive reputation was that bad. The Royals should be held partially to blame for this, as it is clear that they've largely mismanaged Butler's defensive development. Rather than hedging their bets, and admitting that he would be a 1B at best, the Royals wasted everyone's time by playing Butler at third and in the outfield for way too long. Then, when he was promoted, time at 1B, in the hundreds of meaningless Royals games he'd participated in, was suprisingly hard to find.

And then, the Royals made Butler the starting 1B for 2009. Whoa.

For months, judging from the thousands of comments here on the game threads, as well as my general sense of the opinion of Royals writers, fans, etc. has been this: hey, Billy Butler has actually been ok at first! Cool!

According to the defensive stats however, he really hasn't been. While no one is arguing that Butler is a net positive at first, we may need to revisit our assumption that he's non-bad. He's probably better than Mike Jacobs, but then again, 99% of all first basemen ever to play the game have been.

• Butler's RZR (used by The Hardball Times) is 8th out of 9 qualified AL 1Bs.
• Butler's UZR is 9th out of 9 qualified AL 1Bs. If you expand that group to include all players who have played 500 innings at 1st (Butler has played 1224, as a reference) Butler is 14th out of 14. His UZR/150 (rate UZR) is 14th of 14th. If you expand to 300 innings played, Butler gets some relief, as Jason Giambi, Andy Marte and Kevin Millar posted worse UZR/150 numbers.
• Butler's comparables at first are not impressive: Carlos Pena, Aubrey Huff, Kevin Millar, Chris Davis, Victor Martinez, etc.
  

To conclude, Butler was 25.3 runs above average in 2009, but he gave back 5.9 runs with the glove. First base is not a hugely important defensive position and guys like Butler have been hidden at first base for over a hundred years. In some ways, a -5.9 score, well out of the Giambi/Jacobs zone (Jacobs posted an otherworldly -13.6 in 2008) is still better than might have reasonably be expected. Unlike his comps, which are mostly older players, Butler might be expected to improve, and perhaps could some day emerge as a player like Paul Konerko, a player who started out bad but worked his way to average.

So let's be real: Billy Butler is one of the worst defensive 1Bs in the American League. He's been so good with the bat that he's still one of the team's best hitters. Nevertheless, with poor defensive players like Alberto Callaspo and Yuni Betancourt seemingly guaranteed of playing time, the Royals have an anti-foundation in place to again be the worst defensive team in the American League again in 2010.