I read a tweet from Wannstedt that went something like this, Nick Barnett played well last season and will play MLB for us in the nickle.
If this is the case, i would temper my expectations.
Full transcript here with lots of detail about what to expect from the Buffalo base defense. In short, Wannstedt tried to keep from committing to specifics, but you can read between the lines and see that he'll favor the "Miami" 4-3 as we expected.Here's the important part of the linebacker discussion (though Wannstedt had nice words for Sheppard later in the press conference).
The beautiful thing about Nick is really nothing has to change for Nick. He was an outside backer last year. He’ll be an outside backer this year. He was our mike nickel in third-down. Nick Barnett had an outstanding year last year. And I learned this at Dallas, our first Super Bowl we had nobody go to the Super Bowl that year and after we go to the Super Bowl and have success as a team I think the next year we had six or seven guys. Were they the same guys? I think they were. But you know how that recognition thing works. Nick had a great year last year. There will be a few changes. I’m over simplifying it. But from a position standpoint, outside in the 4-3, inside in our nickel package that will remain the same.
Though there were subpackages in which Sheppard played when five DBs were on the field last year, it again would seem that the Bills would prefer Barnett as the primary nickel backer. Wannstedt didn't specifically say that Sheppard wouldn't play in the nickel, but there's no reason to flip the two roles in subpackages. If Barnett slides inside, Sheppard isn't flipping to a nickel OLB role.