Hello! I'm new here, and sorry to jump right in with a fanpost, but here it goes.
The following is more of an idea for future analysis than a finished product. What got me thinking was Fangraphs' popular "#6org" series, which attempts to measure the values of each of the franchises. Fangraphs also does another popular series on the top 50 contracts in baseball.
I wonder if you could combine the two series into a mega-series. What if instead of just assigning a number to each of the franchises, you added up the worth of all the contracts on the team? For example, on the Mariners, Felix Hernandez clearly is a plus to the franchise, whereas Chone Figgins is a minus (they would dump him if they didn't have to pay his salary). So in my ranking of the value of the Mariners's system, I would add Felix's contract but subtract Chone's. What you get is kind of the baseball version of GDP.
I don't have enough knowledge of the Mariner's farm system to judge its total value, so I can't give a Mariner's "GDP." However, I did form a top ten contract value list.
My method: I uses Cot's Contracts, a 40-60-80% arbitration estimate, Marcel-esque 3-4-5 projections (I didn't account for aging), and free agency compensation estimates for the major league players. For the minor league and first and second-year players, I used Victor Wang's research on the monetary value of prospects. For the first and second-year players, I tried to judge where they would be on prospect lists if they were still in the minors. I know this is very rough, but its more of a concept than a final product.
What this shows us about the Mariners: There are a lot of prospects and young players on this list, which bodes well for the future. Also, the gap in value between Pineda and Ackley is somewhat surprising. Teams do not value pitchers nearly as much as position players because of the risk of injury. We should not be surprised if the Mariners trade one of Danny Hultzen, Taijuan Walker, James Paxton, and Michael Pineda in the near future.
Some bonus values: