Evaluating a Player's Value: Trade Edition

The question is specifically about Alex Cobb, but I get this kind of query all the time during the regular season:

Who would you consider a comparable value bat to Cobb in 5x5 AL only?

The real question here is: how do I figure out what Alex Cobb is worth in trade?
For many of my Twitter followers, they want me to directly answer what hitter they should ask for in exchange for Alex Cobb. For me, that's a hard question to answer without knowing your league, how your categories are shaking out, and what your needs are. I try to give some guidelines as far as this goes, but generally speaking all I'm doing is making a very rough guess as to what Alex Cobb is worth in someone's league.

If you're interested in learning how to fish as opposed to me handing you a fish, here are a number of different ways I look at a player's value. Since Cobb was the pitcher someone asked about, here is a step-by-step walkthrough of my thought process on Cobb.

Raw Earnings: Cobb is on pace to earn $11 in A.L.-only, 12-team 5x5 this year. However, since he came up in May, his earnings would be higher if he had put up the same numbers with the Rays all season. You could look at Cobb as an $18-22 pitcher using this method.

FIP/xFIP: Cobb's FIP/xFIP indicates that his core skills might actually be a little bit better than his 3.82 ERA indicates. Cobb's xFIP is 3.35. His LD% and BABIP indicate some luck in the other direction, though. We often put a significant amount of emphasis on BABIP and xFIP, but adjusting for the differences adds two hits and removes two earned runs from Cobb. This does nothing to change his $11 earnings.

Eye Test: We don't like to use the eye test over raw numbers in real life, but in fantasy this is a good way to get a gut feel for what a player is worth. Cobb might be a "true" $20 pitcher, but you're probably not going to be able to get a $20 hitter for him because he's not established. My gut says he's going to get you a $13-15 hitter. Interestingly enough, the hitters in this range are dominated by a number of disappointments or so-called buy low candidates. Justin Morneau - who I have earning $13 - seems like a fair get for Cobb to me. So does Mitch Moreland ($16). Again, you have to use some common sense. Eric Hosmer ($13) might be "fair" based on earnings to date, but Hosmer's owner isn't going to move him for Alex Cobb. He's going to either maximize his investment via trade or hang on until the bitter end to Hosmer.

In the end, the value of a player in trade is what you can get for him. Cobb's market is going to be determined by your league, how much your fellow owners value young pitchers versus grizzled vets, and whether or not they believe Cobb is for real. My process tries to take all of this into account but - ultimately - the decision on what Cobb is worth is yours, not mine.