The Chicago Cubs have been very active this offseason after starting off slow, adding catcher Miguel Montero via trade and pitchers Jon Lester, Jason Hammel and Jason Motte via free agency. While all of these moves should majorly improve the Cubs in 2015 and beyond, one move qualifies as the biggest steal. 

That move was the Montero trade, which gets overlooked since it was made around the same time as the team signed Lester to his megadeal

The Cubs sent minor league pitchers Jeferson Mejia and Zack Godley to the Arizona Diamondbacks in the deal. While Mejia, who went 2-4 with a 2.48 ERA in the rookie league last season, has some upside, he was well worth dealing for Montero. Godley recorded 15 saves in Class-A ball last season, but he’s already 24 years old.

Money was the biggest factor in this deal. The Cubs took on Montero‘s three years and $40 million remaining on his contract, so the Diamondbacks didn’t need much in return. Mejia and Godley both are low-level pitchers who could pan out, but as of now, neither of them is close to being major league-ready.

Chicago benefited by being willing and able to pay Montero, while Arizona wanted to shed salary. He will replace current catcher Welington Castillo, who could be traded by the end of the offseason, per Jeff Passan of Yahoo Sports (h/t D.J. Short of Hardball Talk). That’s because the team could sign veteran and Lester favorite David Ross, according to Paul Sullivan of the Chicago Tribune. Additionally, the team likely feels prospect Kyle Schwarber can step in once Montero‘s contract has expired.

Montero is an upgrade offensively from Castillo, who had another disappointing, injury-riddled season in 2014. The former D-backs backstop hit .243 with 13 homers and 72 RBI last season, while Castillo hit .237 with 13 homers and 46 RBI. 

Clearly, the areas in which these two are separated are their ability to drive in runs and their ability to get on base. In terms of average and power, the two had almost identical numbers. However, Montero had a .329 on-base percentage, while Castillo’s was .297. Also, with the same amount of home runs, Montero drove in 26 more runs.

Perhaps more importantly, Montero is a left-handed bat. That will give the Cubs’ righty-heavy lineup some more balance.

While they’ve made several nice moves this offseason, the Cubs’ biggest steal so far was their trade for Montero. It gets overlooked, but having his bat in the lineup is going to be a major boost. They didn’t have to give up top prospects and aren’t really paying a ridiculous salary.

When it’s all said and done, this could be one of the moves people look at as a reason for the Cubs becoming competitive somewhere down the line.

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