Trevor Hoffman By The Numbers

By now, everybody’s heard about the new addition by Doug Melvin—closer Trevor Hoffman joins the crew. Let’s take a look at what we might be able to expect out of him this year. Here, we’ll take a look at three different pitching metrics—ERA, FIP, and tRA to get an idea of what we might expect out of Hoffman.

First, let’s look at ERA. I’m not a fan of using ERA to judge pitcher talent because there are too many other variables involved—mostly defense, and also luck. Still, it is sometimes worth looking at. I’ll also look at ERA+, which measures against the league average, and, more importantly, is park-adjusted for how easy it is to pitch in Petco (or how difficult it is at Coors). For ERA+, 100 is average, 80 is 80% of average, and 120 is 120% of average.

Year	ERA	ERA+
2006	2.14	189
2007	2.98	135
2008	3.77	101
Career	2.78	144
Projected 2009: Marcel (NOT park adjusted)	3.74	-
Projected 2009: Chone (Park adjusted)	4.17	-

OK, well this here says that Hoffman is on a pretty clear design, but I’m not quite convinced just looking at this metric. Let’s try again with FIP. FIP stands for Fielding Independent Pitching, and is based completely on K/9, BB/9, and HR/9 (things of which the pitcher has complete control). Unfortunately, I don’t have FIP+ numbers for this, but we might still see some trends.

Year	FIP
2006	3.46
2007	2.94
2008	3.99
Career	3.00
Projected (Marcel)	4.00
Projected (CHONE)	3.90

Well, we don’t really see that same trend here. His FIP was very low in 2007, although it spiked last year due to a major rise in HR/9 (.31 in 2007 to 1.59 in 2008). That will probably regress a little bit, but consider that a move to Miller Park from Petco Park will also lead to an increase in HR rate. I still expect it will go down, however, because the last time Hoffman had a HR/9 even comparable to 1.59 was in 2001 (an era with many more HRs to boot).

Year	tERA	tERA*
2006	3.47	3.97
2007	2.44	3.74
2008	3.38	3.26
Projection (Marcel)	3.42	3.84

Alright, so we see two different things here. One thing to keep in mind is that Hoffman will get a good amount of contact, and if he’s giving up a bunch of line drives, it won’t matter that his fielding-independent stats look good. A metric that looks both at the fielding independent rates as well as batted ball data is needed here.

That metric is tRA. To see the backbone of tRA, check out statcorner. Luckily for us, there’s also tRA*, which is park-adjusted and is a better indicator of true talent (it also regresses highly volatile HR/FB rates and other such rates towards the league average).

Unfortunately for us, CHONE doesn’t project tRA, so we’ll have to rely on a Marcel-type analysis for this. I’ve adjusted tRA, which is based on Runs/9 to tERA, which is based on Earned Runs/9. To do this, simply multiply tRA by .92 (92% of runs are earned).

Well, here the trend that we saw using ERA is completely reversed. I’d say that expecting a decline is just as likely as an increase in production. So right now we have a range of projections that goes from 3.7 to 4.2 earned runs per nine innings.

Given potential error with projections, let’s expand this range from 3.5 to 4.4. With replacement level set at 4.65 runs per nine for RPs, that means that Hoffman is somewhere from 1.15 to .25 runs above replacement per nine innings.

So that means if Hoffman pitches 50 innings, he’ll be worth anywhere from 1.5 to 6.5 runs above replacement. Almost there!

Applying the average leverage index for closers (1.93), we get a total leveraged runs saved of 2.9 on the low end or 12.5 on the high end. So Hoffman could be worth anywhere from .3 WAR (1.2 million dollars) on the low end or 1.3 WAR (6.1 million dollars) on the high end.

Clearly we overpaid, because Hoffman would have to basically be above the best projection we have for him to be worth his contract. However, given the closer market, I’m not totally disappointed by this . We’re not handcuffed for the future and it’s a given that Hoffman will at the very least eat up important back end innings. Also, it gives us that “veteran presence” we so dearly need.