The Cincinnati Reds put together an aggressive offseason, and a part of that was acquiring reliever Sean Marshall from the Cubs in a trade. Marshall was set to become a free agent after the year, and the Reds didn't want him for just the short-term. So they got to work trying to get him signed to an extension, and Monday, Marshall and the Reds have agreed to terms.

#reds announced 3year extension with Sean Marshall

— John Fay (@johnfayman) February 27, 2012

We don't know about the money just yet, but now Marshall's under contract through 2015. He'll earn $3.1 million in 2012, and it wouldn't be surprising to learn that his extension's worth something in the neighborhood of $15 million. Marshall will get a lot of money for a reliever who isn't a closer (yet), but for a reliever, Marshall has been extremely valuable.

The last two years, as a Cub, Marshall posted a 2.45 ERA, with 169 strikeouts and 33 unintentional walks in a hair over 150 innings. Put less statistically, Marshall has been awesome, and the Reds figure he'll continue being awesome. The 29-year-old lefty looks to be one of the better relievers in baseball, capable of shutting down lefties and righties alike.

This year, Marshall's going to set up for closer Ryan Madson. If the Reds make a run for the playoffs, though, Marshall's probably going to be a big part.

UPDATE

Deal's worth $16.5 million. Interestingly, there are incentives based on games started and games finished, meaning the Reds haven't closed the door on someday putting Marshall in the rotation.