The Athletics have traded Trevor Cahill and Craig Breslow for Jarrod Parker, Collin Cowgill, and Ryan Cook from the Diamondbacks.
Cahill had a 3.5 WAR in 2011, and a WAR average of 3.13 over the past 3 years. He did this all at 440,000 and under a year. However, he will make 3.5 million dollars in 2012, a still really nice 1118 WASP. He had a PE of 1.86 in 2011, with a .302 BABIP. His FIP - was 105, and his SIERA was 4.02. This is hardly impressive, but he did have a decent 9.27 TR. Cahill is an above average starting pitcher at a decent salary, but his value can be overstated.
Breslow had a .5 WAR in 2011, but has a WAR average of 1.07 over the past 3 years. He is arbitration eligible, but you can expect him to make more than the 1.4 million he made in 2012. If theoretically we said he would make 2 million dollars, he would have a 1869 WASP, a good number. So the Diamondbacks get two underpaid players according to WASP. He is a reliever and had a really poor PE of 1.54, with a BABIP of .342. While that high BABIP is part of the explanation it is not all of it. He doesn't have a very good strikeout rate for a reliever, but did have a FIP - of 91. His SIERA of 3.95 for a reliever is not overly impressive, but he is above average.
Cowgill has just 100 Major League plate appearances, so it only makes sense to look at his minor league numbers. He has 456 PCL plate appearances, and had a .430 OBP, .984 OPS, 2.12 PPG, and 1.97 PAPP. When converted into International League numbers, they look like this: .400 OBP, .906 OPS, 1.82 PPG, and 2.22 PAPP. This is a very nice 5.36 Simple WAR. Converted to the Majors, this is a 3.87 Simple WAR (worth 11.6 million dollars according to the Halladay Standard, and thats just his offense), with an OBP of .354. Defensively, he had an above average Range Factor and a below average fielding percentage. So we could say he is average at defense (but above replacement). He will make the league minimum $480,000 in 2012.
Jarrod Parker has pitched in just 1 Major League game, and has not pitched even in AAA. However, in 209 AA innings, Parker has a -.43 PE as a starter. He has a reasonable walk rate, and doesn't give up very many homers. His AA FIP is also lower than his ERA, which is a good sign.
Ryan Cook has also just pitched 7.2 innings in the Majors and 22 innings in AAA. In his minor league career, he has pitched both as a starter and a reliever. His PE isn't very impressive at .11. He too has a reasonable walk rate and doesn't give up very many home runs.
The Athletics are able to dump some salary and get a very good hitter in Cowgill, but the Diamondbacks get two underpaid pitchers. Most of this trade is going to depend on how Parker and Cook turn out for the A's, but at this point, I think it is pretty even, the Diamondbacks playing for the present, while the A's are playing for the future.