I'm not sure there is a definite answer -- one way or the other.
I was going to use Bulluck as a fascinating case study in a future RTD subscriber column -- and still may -- but I'll put the highlights of the argument here as well.
There are three potential larger issues to consider.
1. The Tennessee defense changed.
I wasn't able to see many Titan games last season, but there were those that suggested that the Titans went to more of a LOLB/ROLB alignment last season rather than a SLB/WLB. Sometimes, that's enough to hurt a former WLB in the boxscore. But enough to cause a drop in solo tackles of over 30 from his prior seasonal averages? And it's not entirely clear that such a defensive change happened. Albert Haynesworth played well, but there didn't appear to be a big increase in the stats of the MLB. And double teaming Haynesworth shouldn't make it less likely that the LOLB/SLB would see fewer blockers. There were also suggestions that Bulluck was used in coverage more frequently. His passes defensed stats don't show a huge increase there, though that's not a clear indication that he wasn't a more frequent cover guy. With Pacman Jones out and the safeties in flux, it's entirely possible that Bulluck had more zone coverage responsibilites. Again, though, that shouldn't have dropped his tackles by 30.
2. The Tennessee defensive tackle opportunity dropped significantly.
In 2007, the Titan defenders had around 47.38 plays per game on which a solo tackle could have been recorded, which ranked 27th overall and below the league average of 49.83. In 2006, the Tennessee tackle opportunity per game was 54.19, well above the league average of 49.62 and the highest in the league. In 2005, the Titans had a tackle opportunity figure of 49.13, barely below the league average and 19th overall. What to make of all that statistical silliness? Well, it could be argued that Bulluck saw significantly less raw opportunity last year -- nearly 112 fewer opportunities over the course of the season. It could also be argued that David Thornton is a much stronger (as were guys like Chris Hope) competitor for tackles, explaining why Bulluck needed the extra opportunity in 2006 to make plays when both joined the team. That argument looks better when you consider that Bulluck's second half of 2007 (without Hope and a gimpy Haynesworth) was much better than his first half (46 solos over nine games to 30 solo in his first eight).
3. Bulluck is on the downside of his career.
Here's the real rub. It's hard to confirm with certainty that the Tennessee scheme and opportunity were clearly worse for Bulluck last year. I could probably form the arguments such that neither were a big issue without too much difficulty. And we've already noted that 30 solos is a huge number, even considering the likely issues above. So, that leaves the potential that Bulluck has lost a half step and is no longer the coverage and pursuit force he once was. He is on the wrong side of 30 now and may not be able to overcome the limitations of scheme, surrounding cast and opportunity that he was once able. The only full game I saw (other than the playoff game) was Bulluck's extremely athletic three interception performace on MNF. He certainly didn't look like a washed up talent then.
Bottom line for me:
I think all three play some role here. In 2008, Bulluck will face many of the same limitations. Hope and Thornton are healthy and competing for tackles. There remains no solid cover corner on the roster, which may necessitate a coverage first mindset for Bulluck. The ball control offense and solid defensive front seven may again conspire to limit overall tackle opportunity. And Bulluck himself is a year older. I think Bulluck is too good to finish under 75 solos again, but I think it's much more likely that he finishes under 88 solos than above. If you can get him as your LB3 or LB4 behind a group of more sure players, he rivals Jerod Mayo, D.J. Williams and the like as the best risk-reward picks of the season.
