The Orioles have agreed to a trade with the Diamondbacks, swapping David Hernandez and Kam Mickolio for Mark Reynolds. This deal moves two of the O’s best bullpen arms (in terms of raw stuff) for a solid third baseman who is hoping for a nice bounceback. The Orioles need right-handed power and, though he strikes out a ton (3-time MLB record breaker), Reynolds certainly offers that. Time to evaluate the trade in terms of value to each of these teams.

Mark Reynolds is owed $5MM for 2011, $7.5MM for 2012, and the club holds a $11MM option for 2013. For this evaluation, I will assume that the Orioles plan to hold on to the third baseman, who will only be 27 on opening day. Bill James projects a .356 wOBA and 17.2 wRAA for Reynolds in 2011. Only UZR really liked his defense last season and historically he has been bad; it is hard to estimate worse than -5 on defense. Third base is worth +2.5 runs per 162 games and he is expected to get 606 plate appearances, worth 20.2 replacement runs. The total package is worth 34.9 runs or 3.5 WAR. Going with $4.5MM per win, we can estimate his value at $15.75MM per year. Given his age, it is also not likely that Reynolds will see a decline in his time with the Orioles so we can guess that he will perform similarly over the life of his contract. This provides $23.75MM of excess value. What sort of value can we expect from the Orioles going to Arizona?

Bill James is much more skeptical of David Hernandez than other people seem to be. He projects a 4.63 FIP and 4.58 ERA over 55.0 innings next season. He also seems to think that Hernandez will start 4 games. Hernandez will likely improve with his role exclusively as a bullpen arm and also a shift to the NL. I would say that going forward, he could be worth 1.0 average WAR per year for the next 5 years, good for 5.0 WAR overall. Then Hernandez becomes a free agent. It is also difficult to guess how much Hernandez might receive in arbitration over that time, but a salary of $400K, $400K, $1MM, $2MM, $4MM seems reasonable. This puts Hernandez’s surplus value at $14.7MM.

Mickolio will see a similar career line in Arizona, though likely with worse results and lower arbitration raises. An average annual WAR of 0.8 for the next 5 years seems reasonable here, worth 4.0 WAR seems reasonable as well. I would expect his salary to go something like $400K, $400K, $800K, $1MM, $2MM. This would be a surplus value of $13.4MM.

On the face of it, this looks very good for the Diamondbacks. The fact is that the market is filled with right-handed relievers right now and that the Orioles could likely find replacements on the free agent market and have already inquired with several. Relievers are also volatile year to year because of sample size issues, making it hard to determine their true talent. The Diamondbacks need relief help and wanted to reduce their team’s total number of strikeouts. The deal seems fair from both sides.