Realizing that DE Michael Johnson is one of the most likely Bengals to get a contract extension during the 2012 season, it's worth discussing what his market value likely is. Keep in mind that most players signing extensions tend to take slightly less than market value since they get guaranteed money now rather than later (or not at all if they suffer an injury).
Looking back at this offseason, there were several players at his position that signed hefty contracts including Mario Williams, Trent Cole, Calais Campbell, Cliff Avril, Robert Mathis, Cameron Wake, Mathias Kiwanuka, John Abraham, Mark Anderson, Jeremy Mincey and our very own Frostee Rucker. Note: Red Bryant and Adam Carriker fall more into the DT category and Kendall Langford and Jason Jones are more 5T or swing lineman rather than a traditional 4-3 DE.
Johnson is not a premier player in the Williams-Cole-Mathis-Avril category. These guys average 9+ sacks each of the last 3 seasons. That group earned an average contract value of $11M/year. The next group includes Wake, Kiwanuka, Anderson and Mincey. These guys average 5.5 sacks each of the last 3 seasons and had an average contract value of $7.3M/year. Rucker averaged only 2 sacks over the last 3 seasons yet still pulled in a contract worth $4.2M/year.
So where does that leave Johnson who averaged 3.8 sacks over the last 3 years? If he can get 8 sacks this year you'd have to put him in the sub-elite category meaning he's worth $7.5M/year. Repeating his 6 sack season would put him just below $7M. Sacks aren't everything (despite what PFF says). With his tall frame, Johnson has knocked down 5 passes/year - that ranks him highly amongst other D-lineman. So basically he's good but not great at several things but that still earns you a hefty contract in this league. I'd offer a 4-year extension worth $6.5M/year with $8M in guarantees (including a roster bonus earned this year to lessen future cap hits).
The tougher question becomes what Dunlap is worth...but that's something we can table until next offseason.