Kansas City Royals third baseman Mike Moustakas has been one of the biggest prospect disappointments of the last few years. Was his struggle predictable?

Maybe it was.

Joseph Werner at Beyond the Boxscore posted this extremely interesting article on July 31st. I was going to front-page it, but I was afraid that it would get buried amidst all the trade deadline reports so I decided to hold off until today. The article is well-worth your time however, so go read it now. I'll even link it as a must-read so you don't have an excuse to ignore it if you'd rather click on a pretty picture than a text link.

OK, now that you've read it, let's summarize.

Werner is working on a new prospect comparison system called CAL. This is based on the Sim Score concept pioneered by Bill James and expanded by Baseball Reference. Quoting Werner, "It's a player classification system whose singular goal is quite simple -- to provide a better context in which minor league numbers can be evaluated by finding closely related players. It's another piece to the analytical puzzle."

According to CAL, Moustakas top minor league comparables were Matthew Sweeney, Edward Salcedo, Miles Head, Matt Dominguez, and Brett Wallace. That's pretty discouraging isn't it. In contrast, the surprising Charlie Blackmon was comparable to Todd Frazier, Nate Schierholtz, Alejandro De Aza, and Craig Gentry. It works for pitchers, too, comparing Kyle Drabek to a bunch of mediocre arms for example, and Gio Gonzalez to Jaime Garcia and Homer Bailey.

I am going to pay close attention to how Werner develops the CAL system since the results he's posted so far look very intriguing. CAL could end up being another valuable tool at our disposal for prospect analysis.