Last week, with the addition of Nick Green off waivers from the Angels, the Brewers were forced to designate Luis Pena for assignment to clear a space on the 40-man roster, a move which led to Pena being claimed by Jack Z. and the Mariners. I haven't exactly seen a groundswell of negative reaction to the move, but I have seen a few people express disappointment over losing Pena, so I thought it warranted a deeper look at both players, to get a better feel for their value.
Pena turned 26 in January, and was signed by the Brewers out of Venezuela prior to the 2001 season. He pitched eight seasons in the Brewers' minor league system.
| Year | Age | Team(Level) | ERA | WHIP |
| 2001 | 18 | Arizona (R) | 4.63 | 1.57 |
| 2002 | 19 | Arizona (R) | 3.49 | 1.41 |
| 2003 | 20 | Beloit (A) | 3.90 | 1.53 |
| 2004 | 21 | Beloit (A) | 3.91 | 1.37 |
| 2005 | 22 | Brevard County (A+) | 4.26 | 1.32 |
| 2006 | 23 | Brevard County (A+) | 4.43 | 1.55 |
| 2007 | 24 | Brevard County (A+) and Huntsville (AA) | 2.63 | 1.04 |
| 2008 | 25 | Nashville (AAA) | 6.93 | 2.05 |
Whatever Pena found in 2007, it certainly took him long enough to locate it. Pena has been somewhat old for his level every year since around 2004. He improved slightly in his second try at low A, but regressed in his second year at high A. With the exception of 2007, he's allowed a lot of baserunners at every level. And, of course, he had a disastrous 2008 season in Nashville.
With that said, Pena throws hard, and a lot of value is put on that skill. If he finds a way to control his stuff he could be a key contributor to someone's bullpen and he's still young enough to have a nice big league career. His control isn't there yet, though, and may never be: Pena walked 47 batters in 49.1 innings in 2008, and has walked 247 in 531.2 career minor league innings (BB/9 of 4.18).
On the flip side, the Brewers were able to fill Pena's roster spot with Nick Green, a 24-year-old starter who has had the following career in the Angels' farm system:
| Year | Age | Team (Level) | IP | ERA | WHIP |
| 2004 | 19 | Provo (R+) | 51 | 3.88 | 1.47 |
| 2005 | 20 | Cedar Rapids (A) | 100.2 | 3.58 | 1.08 |
| 2006 | 21 | Rancho Cucamonga (A+) and Arkansas (AA) | 177 | 4.32 | 1.31 |
| 2007 | 22 | Arkansas (AA) | 178.1 | 3.68 | 1.10 |
| 2008 | 23 | Salt Lake City (AAA) | 159 | 5.32 | 1.45 |
Green's 2008 numbers probably deserve a slight adjustment, as Salt Lake is one of the friendlier run-scoring and home run environments in the PCL. Even so, Green was a solid performer who pitched a lot of innings while young for his level in AA in 2007, and assuming he can bounce back from a tough 2008 campaign, he could be an option to produce a fair number of league average or better innings for many years down the road.
So, what do you think? Was exchanging Pena for Green a good idea?