How much destruction can Nate Robertson cause?

In the wake of the biggest piece of news Marlins fans have had since the Josh Johnson extension (which is sort of sad for us), Nate Robertson has us Marlins fans jabbering a lot more than usual. Part of it is the general excitement of is having something new to talk about, but another part is the concern fans have for acquiring a pitcher who isn’t so good and having to give up stuff to get him. You can check some of those opinions and concerns over at FishStripe’s thread discussing the trade.

Fist off, we did not give up a whole lot. John said that Jay Voss was unlikely to crack the big league roster anytime soon, and it’s never a good sign to see a pitcher start off as a starter and get transitioned into a relief role in High-A, especially for a lefty. But what about the concerns of Robertson being bad? Certainly those are legitimate given his recent struggles and his already mediocre track record.

Well, yeah, if you’re concerned about that, you are paying attention to the right things. But let me alleviate your concerns. What’s the worst Nate Robertson could possibly do?

The Worst Case Scenario

What is the worst Nate Robertson you can imagine? PECOTA’s 10th percentile projection, which is the worst possible, projects a 5.35 EqERA, which is based on his component statistics. I don’t buy it, in part because PECOTA seems very flat about his possibility of decline (maybe he can’t get much worse than this?). Based on that line’s FIP components, I got a FIP of 4.86, not terribly awful, especially after his last two seasons.

Let’s look at it at those two levels. Let’s say that, at his worst, Robertson would be given 10 starts averaging 4 2/3 innings per start (because he’s so awful). At a 4.87 FIP, that performance would be worth 0.2 WAR. At the absolute worst imaginable result, Robertson ends up as a replacement level pitcher, essentially a Quad-A guy, worth 0 WAR in those same innings.

Those who were disappointed with this trade stated that Rick VandenHurk would have been a better choice. I generally agree, but the Marlins’ brass did not. Clearly, VandenHurk was not going to start the year as the fifth starter given Clay Hensley’s performance in Spring Training. Was that wrong? Absolutely. The team should have recognized that Hensley was not a better pitcher than Hurk, even with the ST performance. But that does not mean we should really be comparing how Hurk would have done in the fifth spot instead of Robertson. Hurk was not an option to start the year, so there was no use crying over his missed playing time. The comparison should be made to Hensley.

Nevertheless, I’ll compare both. First, let’s start with Hensley. Let’s say Hensley is given a little bit more time, an average of five innings per start in those 10 starts. Yesterday, I took a bunch of projections for the Marlins’ back-of-the-rotation guys and got an average FIP of 4.99 from three projection systems for Hensley. That would have added up to about 0.2 WAR. In other words, there’s very little difference between having Hensley or Robertson out there.

Next, let’s consider VandenHurk. The average projected FIP I saw for Hurk was 4.42. Let’s give Hurk even more innings, let’s say 5 1/3 per start. That means that over 53 1/3 innings, you would expect 0.5 WAR from VandenHurk.

The Grand Finale

I took the worst Nate Robertson we could think of that would still be a fringe major leaguer, aka a replacement level Robertson, and compared him in 10 starts to both Clay Hensley and Rick VandenHurk. Compared to Hensley, Robertson’s replacement level version would cost us at worst 0.2 wins. Compared to VandenHurk, that total goes up to 0.5 WAR. Now, half a win is a lot; for example, evenly-matched teams begin with half a win in their pocket to start a game. But that’s at the absolute projectable worst Robertson could be. If he’s any better, then we’re looking at differences around 0.2-0.3 WAR, and who is really noticing the difference between a third and a fifth of a win?

Of course, Robertson could flop entirely, give up 15 runs in 12 innings, and get released, but then we’re talking extremes. VandenHurk could do the exact same thing. Robertson could pull a 2009 Jarrod Washburn and turn into a decent pitcher for a few months. There’s no reason to speculate at the extremes. The worst I would expect is replacement level, and at that level his destruction would cost us at most half a win over our best choice, who probably would not have been the starter. Once we move to reasonable levels, the performances become more difficult to distinguish, so there’s no need to be so drastically concerned.

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Tags: Clay Hensley Miami Marlins Nate Robertson Rick VandenHurk

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