If you haven't noticed already, MILB.com has a cool feature where you can look at all winter league stats by organization. Here's the Pirates'.
Most of the offensive numbers are nothing to write home about. In the Arizona Fall League, Andrew Lambo and Tony Sanchez are hitting fairly well, but this is in a league where wild offensive numbers aren't uncommon. Josh Harrison and Jordy Mercer haven't hit much at all so far. Among the Bucs' pitchers, Justin Wilson and Aaron Pribanic have pitched well.
There's some interesting action going on in other winter leagues as well. Andy LaRoche continues to not hit at all in Venezuela - in a very small sample, sure, but there really seems to be something going on there. As Dejan Kovacevic pointed out a few weeks bat, LaRoche doesn't even in the ball hard in batting practice anymore. Even if LaRoche doesn't really have the goods to be a major leaguer, he should be able to hit winter league pitching if he's healthy, and he should certainly be able to hit well in BP. If he isn't healthy - if his back is still bothering him - that might explain a lot. In any case, the Pirates will probably non-tender him this winter.
Another interesting line belongs to Rogelios Noris, the Class A outfield prospect, who's hitting .294/.385/.529 in Mazatlan of the Mexican Winter League. The MWL is higher-quality baseball than the South Atlantic League, where Noris played this year - a lot of MWL players are or would be Class AA or Class AAA guys in the U.S. minor league system. And yet this is the second year in a row that Noris has put up great numbers there. He hit .236 for West Virginia this year. It could just be a fluke, or he might really just love playing for his hometown team - he was born in Mazatlan.