One of the things that I find odd is the coveting, by some Rangers fans, of Nate Robertson, the suggestion that the Rangers should be targeting him and trying to pry him away from the Tigers.
Robertson is a lefty who just turned 29 a little over a month ago, and who, prior to this season, had been just another mediocre starting pitcher. He posted a 5.44 ERA in 8 starts in 2003, then followed that up with two full seasons in the Tiger rotation, posting a 4.90 ERA in 2004 and a 4.49 ERA in 2005. That's not real good, pitching in the CoPa...his ERA+ for those two seasons was 92 and 95.
Then, in 2006, he seemingly broke out, posting a 3.84 ERA in 208 2/3 IP, good for a 118 ERA+. Yes, he's rather old to be having a breakout year, the Robertson fans say, but lefties develop later in their careers. And besides, 2006 was only his third full major league season, so it shouldn't be that surprising that it took him a while to adjust and figure it out. But now that he has, he's the type of pitcher the Rangers should be targeting.
Here's the problem, though...despite the 3.84 ERA, Robertson really wasn't all that good this year. Take a look at his peripherals over the last 3 years:
| Year | K/9IP | BB/9IP | HR/9IP | GB/FB | Dips ERA | ERA |
| 2004 | 6.4 | 2.7 | 1.1 | 1.64 | 4.53 | 4.90 |
| 2005 | 5.5 | 2.9 | 1.2 | 1.59 | 4.81 | 4.48 |
| 2006 | 5.7 | 2.6 | 1.0 | 1.46 | 4.69 | 3.84 |
So, what is the upshot of all this?
Robertson's performance, if you look at his peripherals and ignore his actual ERA, has been about the same the past three years. His DIPS ERA and peripherals reflect that he hasn't been a real good pitcher in any of the past three seasons. And his GB/FB ratio has actually gotten steadily worse during that time. There is just one number that stands out as an aberration, when looking from year to year...his 2006 ERA...
Nate Robertson's breakout 2006 performance was due, primarily, to having a very good defense behind him, and getting lucky. He was third in the A.L. in DIPS% (his DIPS ERA divided by his real ERA, which reflects how much he overperformed his expected ERA). Detroit's Kenny Rogers was second, while Justin Verlander was fourth, which supports the notion that Detroit had a terrific defense playing behind these guys this season.
Nate Robertson might very well be on the trade market this winter...if I'm Dave Dombrowski, I'm floating Robertson's name out there to see if someone wants to overpay for a lefty with a pretty ERA, particularly given the other starting options I have available to me.
But personally, I also hope that the Rangers let someone else overpay for him.