Evaluating the Nathan Karns trade

Late last night, the Tampa Bay Rays traded pitcher Nathan Karns to the Seattle Mariners, along with lefty reliever C.J. Riefenhauser and outfield prospect Boog Powell for shortstop Brad Miller, reliever Danny Farquhar, and first-baseman/DH Logan Morrison.

That's a large deal, with  a lot of moving pieces, and it will take some time to digest and analyze all of them, but one thing is immediately clear: Yasiel Puig is in no way a part of the trade. And that's a shame.

This past season, as the trade deadline approached, I wrote an article claiming that Yasiel Puig was a reasonable return to expect from a Nathan Karns trade.

That trade wasn't my idea (it was being bandied about twitter at the time), but I ran the surplus value numbers and came up with Karns as being worth around $60 million over the span of his existing contract, and Puig being worth somewhere between $75 million and $55 million.

Well, now Matt Silverman has traded Karns, and he probably got about half a Puig. What gives?

The Return

Let's review the concept of surplus value for a second as our go-to trade evaluation method. It's based on the idea that baseball production is a liquid asset, and that for a team working on a budget (which is for the most part, all teams), getting good production from one player without paying him a lot allows a team to pay for more production from a different player.

To calculate it, you convert expected production into what it would be worth on the average free agent market, and then subtract from that what the player will actually be paid over that span of time. Jason Hanselman outlined the method here.

Riefenhauser and Powell, despite being potentially useful, should be projected for negligible surplus vale, so the Rays side is all about Karns.

And looking at the return in this trade, it's really all about Brad Miller, at least as far as surplus value is concerned.

Danny Farquhar has years of team control and major upside out of the bullpen, but he simply wasn't very good last year. He's a fantastic reclamation project who the Rays won't have to pay a lot for over the next four years, but don't mark him down for anything on the spreadsheet where they actually play the games.

The same goes for Logan Morrison, only without all the upside. Steamer projects him to be a league-average bat at a premium position of first base. That's not worth much, and at $4 million for one year, you're paying for less than half a win (if he plays defense), so Morrison's portion of the trade is a wash as well.

But Brad Miller does have value. He too will be under contract through 2019, and so far in his career he's demonstrated the ability to produce league-average offense, and to play average defense at shortstop (which is above-average defense overall).

Miller's time in the outfield last season was disastrous, but if you remove that experiment from the equation, you have a guy easily poised to produce 2.0-2.5 WAR for the Rays, depending on playing time and whether he is platooned against left handed pitching.

Using the higher WAR estimate of 2.5, that comes out to around $30 million in surplus value. The lower WAR number would put Miller at around $22 million.

That's a fine return, generally, and a good chunk of value, but let me go ahead and state the obvious: $30 million is less than $60 million.

What happened?

Well, for one thing, a decent chunk of Karns's surplus value (in these calculations, it was around $10 million) was actually tied up in the end of the 2015 season, when he was pitching well and being paid league minimum. For all of these players, their value now is lower than it was at the trade deadline.

On the other hand, and seeming to contradict that point, Karns actually pitched pretty poorly down the stretch, with fielding independent pitching (FIP) marks of 5.07 in August and 5.80 in September. These struggles were partly due to a jump in his HR/FB, and partly due to an increase in his walk rate.

It's certainly possible that Karns could improve on his 2015 performance, and that FanGraphs WAR (which is based on FIP) is also not the best way to project Karns, but in retrospect, the 3.0 WAR mark I used in the previous article now looks like wishful thinking, particularly with Karns now recovering from the dreaded "forearm tightness."

Currently, Steamer projects Karns to be worth 1.8 WAR over 180 innings pitched. Rounding that up to two wins, and plugging that into a calculation that assumes half-WAR dropoffs each year to account for risk, and 40-60-80 arbitration values, we get . . . $31 million.

Or half a Puig.

Conclusion

Sure, it's not what we hope for when we talk about trading a young cost-controlled starter, but Nathan Karns isn't actually young. And while it's certainly possible he'll produce that three-WAR season I thought he was capable of when I looked at him at the trade deadline, the simple truth is that he hasn't yet, and decline is usually a better bet than improvement.

And in that sense, Karns and Miller are the same. They're both under team control for several years, they both have the ability to help their team win right now, they both have the ability to improve their numbers, but neither should be penciled in for the All-Star game.

Clearly, Silverman wanted to shift some of the value in his team from the mound to the field, while Jerry DiPoto wanted to shift it the other way, so they were a good match in a trade that no one "won." Starting pitching was a position of depth for Tampa Bay, short stop was a position of depth for Seattle.

This is a balanced trade.

It's just a shame we didn't already have Brad Miller on the Rays, because then we could surely have sent him and Karns to Los Angeles for Yasiel Puig.