As reported yesterday, the Chicago Cubs have bought out Sean Marshall’s remaining two years of arbitration for $4.7 million – $1.6 million in 2011, and $3.1 million in 2012. After making less than a million in 2010, it’s a nice raise for Marshall.

But it’s an absolute steal for the Cubs.

Last year, Sean Marshall was the fourth most valuable reliever in the National League (with a 2.2 WAR, a 2.65 ERA in 74.2 innings). And yes, it was his best year by far, but for his career, he’s always been dominant as a reliever: 2.89 ERA and 149 Ks in 143.1 innings. Clearly, based on past performance, Sean Marshall is an elite reliever.

And he’s getting paid like a mediocre one.

Sure, the arbitration raising process plays a primary role in it – players almost never achieve “market” value in arbitration. But when a guy like Hong-Chih Kuo, who bested Marshall in the traditional stats, but whom Marshall equaled in the advanced stats, is about to get $3 million in his second year of arbitration, you have to wonder whether Marshall could have received more.

All in all, if he’s happy, I’m happy. It’s a great, great deal for the Cubs.