The Packers had Buffalo's free agent OL Duke Preston in for a visit:

"I had chance to meet him," McCarthy said. "I was very impressed with Duke. Very bright. I like the way he presented himself. I found it to be a very positive visit. As far as where we we’re at with the negotiation, I don’t have anything for you. But I liked him. I didn’t know much about him until he came in. He can play both positions [center and guard]."

Just like Mike McCarthy, I had no idea who the heck Duke Preston was until he came to town. Apparently there is a lot to dislike about him, from Buffalo Rumblings:

Specifically, people have been questioning whether he should be re-signed as depth now that Buffalo has picked up Hangartner to start at center. Short answer? "No." Long answer? "Hell no!"...

There's also no point whatsoever in bringing Preston back as depth. After all, if a guy has proven that he's incapable of starting, what's the point of having him on the roster? It would be one thing if Preston was an unknown quantity like Demetrius Bell or some other rookie. Preston has demonstrated that his ceiling is the roof of the basement.

If you want confirmation that he sucks, apparently the Oakland Raiders and their fine scouting department are interested in him too.

Just say no, Ted, just say no.