Matt Guerrier is a few people's favorite Cub. "How could this be possible?", you may ask. Well, his presence on the team means Carlos Marmol's presence isn't. That's a win for many people who just wanted Marmol and his $9.8 million contract out of Chicago. Honestly, I don't really mind if players are overpaid (I care only from the abstract payroll sense, and Marmol's contract has never been the difference between the Cubs being competitive or not), but I can't deny there was a stigma surround him. However he's not on the 40-man roster. Matt Guerrier is.
Matt Guerrier was drafted in 1999 by the White Sox. He was a 10th round selection of out Kent State University. He started as a reliever, but found some success in 2001 as a starter for AA-AAA. He was traded to the Pirates in 2002 for Damaso Marte and Edwin Yan, and he did not do well there in AAA. He had an ERA of 4.59 and 4.53, respectively, and was waived where he was claimed by the Minnesota Twins. He did better as a starter there in 2004, with a 3.19 ERA as 25-year old. He had a cup of coffee in their bullpen; after that, he broke with the camp for (essentially) good. He was a very good reliever from 2005 to 2010, but has sputtered since signing a 3 yr/$12 million contract with LA (1.5/4.75/4.75).
It's hard to get a handle on Guerrier's pitch selection. Pitch F/X freaks out and claims Guerrier dropped his slider in 2011 (which he used 40% of the time) for a cutter…but they are essentially the same pitch, thrown 83-90 with some y break and little x break. It doesn't move very much for a typical slider/cutter, but he also throws it to contact more often than the average guy. He throws a fastball 45% or so, and it moves around 90 mph (touches 93). Funnily enough, it's his better pitch the past two years, and his "out" pitch, as it were. It does a decent job of handcuffing righties. He also offers a curve that comes in at 78 and runs 10 to 4; it'd be a real weapon as a change of plane pitch if he had any handle on it, but he doesn't.
It should really be more like "Stuff." Guerrier doesn't have any; he has a 6 K/9 percentage, which is bad. 15.9 K%, 7.8 BB% just aren't great numbers. It's added up to a 4.34 FIP (which he's generally always beaten: career ERA is 3.53). "Luckily" for Matt, his BABIP for his career is .266. Since he puts so many balls in play, he's going to be overly dependent on defenses to bail him out (and the Dodgers had a shit defense that buried him this year). Guerrier isn't a flyball or groundball pitcher, either, he's just a pitch-to-contact guy. That's not a great skillset in a reliever.
Matt Guerrier is basically a janitor at this point in his career. He's not a guy that you can call on to throw flames and get a strikeout, and he isn't a starter (and doesn't have a 3rd offering to ever be one). He's 34, so his best days are behind him. He's not even really a ROOGY (.319 to .290, wOBA-wise). Guerrier is a fungible reliever that can eat up innings and not be all that bad. He's not worth the 4.75 million he's paid, but he's probably worth the little we saved by shipping Marmol to LA.