Yoanner Negrin is sort of an enigmatic fellow. He signed with the Cubs in 2011, when he was 27 YEARS OLD. He wasn't exactly a premium prospect; I can't find any information on what he signed for. The expectation at the time of the signing was the he preferred relieving, but his arsenal of pitches were such that it made sense to try the whole starter thing eventually. In 2011, he went from Rk to A+ (at 27). In 2012, he made his way up to the PCL, but played primarily in the Mexican League (where he was pretty bad, all things considered). He started 20 of 28 games there.
Yoanner spent the entire year at Iowa. He was used mostly as a reliever, though he started 14 games (a few of those were piggyback games). His peripherals were sound; 24.7 K%, 6.5 BB% (both vast improvements over his MexiLeague stint), and it all came together in a 2.79 FIP. Unfortunately, he was extremely hit-unlucky (.380 BABIP), fairly strand-unlucky (68.1% LOB), and the combination of the two factors put his ERA at a pedestrian 4.17. Still, the season wasn't a total wash; he did pitch 108 innings with 118 strikeouts to just 31 walks. Those are numbers that will play in the majors.
Part of the reason I really like Negrin is his pitch selection. This is what John Arguello had to say when he was signed:
Negrin can throw 90 MPH consistently with his fastball and can reach as high as 94 MPH. Negrin throws four seamers, sliders, changeups, curveball and two seamers.
He pulled that from an interview with Carlos Perez, from the Wasserman Media Group. In reality, he throws even more pitches than that. He can change his arm angle and give players a lot of different looks. It'd be really hard to sit on a pitch with Yoanner, though he can only really dial it up to around 92. The lack of premium velocity means he's going to have some games where his lack of control leads to early chases, I'd presume.
I said that Trey Masek's 6'1" could lead to flat fastballs, but Yoanner is only 5'11" (as is Corey Black, from dmick's preview). Negrin isn't adding any muscle or velo to his frame, so it's really hard to envision him as a starter at this point. I'm not calling Negrin a soft tosser, but his stuff might play up better in relief.
Negrin is definitely in the mix for the bullpen in Chicago next year, but he'll have some pretty stiff competition based on where he is on the 40-man roster (he's not on it). Negrin isn't 5 eligible next year, but at some point, you've got to see if the 30-year old has it. I imagine he either breaks camp with the team or is the first man up in 2014. He has the ability to be a swingman like Carl Newhouse this year, which is a decent place to be (albeit not with much upside).