AaronGleeman.com

Later this offseason I'll be putting together my annual "Top 40 Twins Prospects" rankings for 2009, but before that happens it's important to evaluate how the team's minor leaguers performed in 2008. When it comes to major-league players most people recognize the need to take things like defense, home ballpark, league, and run-scoring environment into account when evaluating their performance, but for some reason those same factors are often overlooked in examining minor-league players.

Putting players' performances in context is even more important in the minors, because the differences between ballparks, leagues, and run-scoring environments are often much more extreme than in the majors. For an example, just look at how different the two Triple-A leagues were this year when it came to offense. As a whole, the Pacific Coast League batted .277/.348/.444 and saw 10.5 runs scored per game. Meanwhile, the International League batted .263/.331/.404 and saw 9.0 runs scored per game.

Most people wouldn't think twice about saying that a pitcher "had a 4.00 ERA at Triple-A," but "Triple-A" can be vastly different depending on the league. A 4.00 ERA in the Pacific Coast League was fantastic in 2008, rating about 18 percent better than average. Meanwhile, in the International League that same 4.00 ERA was actually worse than average. In fact, a 4.00 ERA in the PCL was roughly equivalent to a 3.35 ERA in the IL, and that's far from the minors' most extreme league-to-league gap.

Beyond leagues, ballparks, and run-scoring environments, factors like age, defense, and track records are also important. For an example, compare Garrett Jones hitting .279/.337/.484 at Triple-A to Trevor Plouffe hitting .262/.308/.415 split between Double-A and Triple-A. With a 98-point edge in OPS, Jones' season appears on the surface to be much better. However, look deeper and Plouffe likely had the more impressive season and is the superior prospect.

Jones was a first baseman playing his fourth straight season at Triple-A and at 27 years old was 2-3 years older than most of his prospect-aged competition. Plouffe was a shortstop who after beginning the season at Double-A spent the second half playing alongside Jones at Triple-A, where at 22 years old he was 2-3 years younger than most of his prospect-aged competition. Putting their numbers into context casts them in much different lights and the same is true for players throughout the minors.

In an effort to provide an even playing field for evaluating how Twins minor leaguers performed in 2008, I've created a quick-and-dirty system that normalizes all leagues and run-scoring environments to fit the level of offense in MLB this season (.264/.333/.416 with 9.4 combined runs per game). I've also put in adjustments for a player's defensive position and age relative to the level he played at, so that guys like Jones and Plouffe (or, say, Randy Ruiz and Wilson Ramos) can be compared properly.

In recent years it's always been easy to look at the Twins' prospects on an organization-wide level and conclude that they're far stronger in pitching than hitting. While that's been accurate for the most part, it's also important to note that the system features extremely pitcher-friendly run-scoring environments at every level. In other words, good hitting prospects or not it's difficult to collectively post great offensive numbers at Rochester, New Britain, Fort Myers, Beloit, and Elizabethton.

Meanwhile, those same pitcher-friendly run-scoring environments have also played a part in the Twins seemingly always having an abundance of quality pitching prospects. Certainly the organization's focus on drafting and success in developing pitchers are much larger factors, but the system's never-ending stream of pretty ERAs can't be credited entirely to great pitching talent just as the relative lack of huge OPS totals can't be chalked up entirely to a dearth of position-player talent.

Over the next few days my goal will be to put all of that into some context.