Back in 2007, Carlos Marmol burst onto the scene in the Chicago Cubs' bullpen. After struggling in his big league debut the year before, he had a 1.43 ERA and an outstanding 12.4 striekouts per nine innings in 59 appearances with the Cubs that year. He wasn't quite as good in 2008, but he still posted a 2.68 ERA and had a strikeout rate north of 11 per nine. Over those two seasons, his 4.3 per nine innings wasn't a good rate, but it wasn't absolutely terrible.
Since then, walks have been a major problem for Marmol. From 2009 through 2013, Marmol has walked a staggering 6.8 batters per nine innings, the worst rate in Major League Baseball among pitchers who threw at 100 innings or more over that span. He's been able to stay in the big leagues because of his strikeout rate, which at 12.6 per nine is the fifth-best rate in the game since 2009. Combined with a pretty good home run rate, Marmol has produced a 3.49 ERA and 3.61 FIP since 2009.
In his eighth season with the Cubs in 2013, Marmol had a 6.18 ERA before he was was traded to the Dodgers in early July for relief pitcher Matt Guerrier. Now a free agent, Marmol doesn't seem like Sandy Alderson's type of pitcher because of his severe problems with walks. He'd be an unconventional signing and would come with plenty of risk, but he certainly has the ability to strike out major league hitters. If Marmol could be had on a minor league deal or a very inexpensive major league deal, though, he could be worth a roll of the dice.