I see one glaring weakness in your lineup, SS. You have some good depth at 3B, and I suggest trading Wigginton for a SS. I also have Wigginton on my fantasy team, and he gave my team a nice boost. However, He will probably wear down, and come back down to life soon. So while he's doing well, i suggest shipping him out.
You also are weak in relief, Duaner Sanchez won't earn your team any saves. Weathers is a below-average closer, and Reitsma might be demoted from the closer spot soon, while Chris Ray is on fire. You might want to trade Guillen for a decent closer, or trade Cabrera for a top-notch closer if you don't want to loose Wigginton in the suggestion above.
If you can fix those small spots, you will easily get into the top 3 for your division
Realistically, I'm not sure what you'll get for Wigginton. Visquel should be OK. He'll get on and score some runs, steal some bases (he's got five already). I agree that you should move Wigginton. He's quad-A at best. I'm not sure about your league's scoring though, and if you're counting errors, I'd walk away from him entirely.
C Napoli 1B Hafner 2B Uggla 3B Upton SS Mig. Tejada OF Juan Pierre, Sizemore, Wells UTIL Carlos Peña BN Swisher, Glaus SP James Shields, Clemens, Lackey, Oliver Pérez, Maine, Webb, Lincecum RP Nathan, Mo Rivera, Al Reyes
I had a feeling that in the begining of the season that my catchers would get me a HUGE amount of points but to my disapointment, both Posada and Jojima aren't living up to my expectations. They are pretty much doing the same so i dont know who to start. Of course i could draft a free agent, im thinking eiether Damian Miller or Miguel Olivo.
Another of my problems is who to start at 2B: Weeks or Freel. Freel is hot now with his 8 stolen bases and .300 Batting average but i have a feeling Weeks will come back.
I think Catcher could become a problem as well as shortstop. Your starting pitching is really solid with the exception of Blanton who is killing 2 of my teams. If you can afford to take a hit in SP I'd try to ship the Gambler and Wiggington for an upgrade at C, SS, or RP