The Cubs have a few interesting names at third, but most of them are quite far away. Depending on how you feel about Vitters (and Baez), you could see some pretty sub-standard production from the hot corner for quite a long time. Where's Aramis when you need him?
The league average 3B wOBA was .320 last year.
Luis Valbuena was the de facto starter at third last year. He can draw a walk and play defense, but not much else. Valbuena is an average utility man that is somehow projected to hit like a league-average 3B next year. If he does that, he'll turn around and be really valuable. I'm not holding my breath. Ian Stewart hasn't been league-average in half of a decade. He says his wrist problems are behind him, but he made no mention of his swinging-strikes problem, so I assume that's still an issue. Josh Vitters was historically bad last year. I try to take solace in the fact that Rizzo's first circuit was awful also, but when you compare the two Vitters makes Rizzo look like Barry Bonds. He'll need to improve immensely.
Diory Hernandez is org filler who is going to filler some other org this year.
Matt Cerda was stolen by our most hated rivals. He was actually quite intriguing; he had mediocre-to-poor power but a great batting eye. He might stick with a major league team in the near future, though he'll likely not be a star. Dustin Harrington split time between AA and A+, and he hit better in Tennessee. Still not impressive at all, though.
Christian Villanueva didn't impress enough to stay on any Top 100 lists, but his season wasn't terrible. He's had some bad scouting reports (including one from Jason Parks on the Bleacher Nation Podcast) as far as great expectations, but I think they are somewhat overstated. Villanueva can be a very good major leaguer if he some things break right, but some things need to break right for basically every prospect ever so that's no surprise. I'd like to see less strikeouts, sure, but isn't that true for everyone also?
Wes Darvill doesn't sound like a baseball player, and he doesn't hit like one either. He's had 4 years in the Cubs organization and has look bad in about 4 of them. I think it's time for Wesley to dust off his resume. Dustin Geiger exploded for 17 home runs last year. He's improved every year as he's climbed the professional ranks. He needs a few more solid efforts to really be thought of as a major league contributor, though.
Jeimer Candelario is a legitimate prospect in most people's estimations, but I have some definite reservations. People were really high on his plate discipline and frame in 2011. His walk rate tumbled to 8.4% last year (still good, but not overly impressive), his strikeouts ticked up (to a still-manageable level), and his BABIP regressed to a more reasonable .327. That was the main factor to his diminished line last year (.281/.345/.396, wRC+ of 113). If he can stick at 3B, a MLB line of .260/.330/.420 makes him league-average (and he might reach those or slightly higher?). At 1B, where I think he probably ends up, that's a AAAA player. I hope he surprises me (and much smarter men than me are very high on Candyman; Keith Law has him #106 overall), and he does have potential; I just don't see it happening. Stephen Bruno has hit the cover off the ball in his 292 professional plate appearances. He had a crazy, impossible .426 BABIP last year, so expect a huge drop in his numbers that might make you think much worse of his skills (he was also hit by an incredible 20 pitches last year). Bruno didn't walk last season, and that'll be an issue down the road. He also doesn't have the size comparable to Candelario; he gives up 4 inches, though only 5 pounds. 2013 will be interesting to see just how much Bruno will regress to the mean.
Ben Carhart annoys me because when you put that in FanGraphs, nothing comes up. He's only listed under Benjamin Carhart. He's got 155 professional PA. It's hard to really put much stock in that, though he did mash the ball and rarely strikeout. Who knows?
All in all, there are some okay pieces at third (the real prize is Baez at short, if he gets to the majors). Considering how good the Cubs' farm is these days, 3rd base is an area of relative weakness. There are some breakout candidates, though, and we'll see just how good these younger players are.