I've read enough material on PD to make some comments, which may even be intelligent (or at the very least I hope it's intelligible).
First, the criticism. He's old. He's slow. He only got two sacks last year. He's got bad wrists and ankles. His numbers have been dropping steadily. He's old.
Second, the praise. He's strong as all hell (Baby-Hippo-Lifting Strong) and can use that strength to move inside on passing downs. He is as crafty a veteran D-end as there is. He stuffs the run. He just won a powerlifting competition and is lighter, stronger and faster (self-proclaimed) than he was last year. He's been healthy all offseason.
Third, my intelligent/ible commentary.
PD isn't going to win sack competitions or give Tom Brady that scared, "I'm getting blown apart and I forgot how it feels" look. However, he will keep containment and shut down the run on his side. In the Detroit game last season there was a point where he bounced a run out of bounds while surrounded by three offensive players (those with excellent memories may even remember that some foo of a talking head said that the skins had the best D-line in the league after that game). It was a savvy and skillful move, and was a great display of what PD does best.
Stats are the nuts and bolts of football analysis, and It's always distressing when your middle aged players turn the corner and no longer put up great numbers. But on the D-line tackles, sacks, hurries and swats don't tell the whole story. Run yardage is another indicator of how well the D-line is doing. The Skins were pretty stingy last season against the run (shutting the door on both the girls and the vikings at the end), and I feel that was due in large part to PD. O linemen who want to run block against PD are forced to deal with his baby-hippo-lifting strength, and tend to get worn down sooner than they do against edge rushers and ends who make their money through finesse. By the fourth quarter LTs become exhausted and their run game ends up wasting comeback time and first down potential, ala the vikings.
Another indicator of D-line performance is how well the LBs are doing. I've read that our LB corps over performed and masked deficiencies in our D-line last year. Indeed, our LB corps is amazing (at least when healthy, I have doubts in the Hamburgular starting in at ROLB), but its excellence was also the result of our D-line sucking up all the blockers and forcing one on ones between the LB and the RB. I know Rocky is a bad ass, but his remarkable numbers last year must have been helped out by PD's ability to flow with the play and prevent linemen and fullbacks from entering the second level. This is evidenced by the fact that there wasn't really a hiccup when Godfry took over for Rocky. Godfry is a solid player, but athletically Rocky is superior. The smoothness of Godfry's transition has to be partially attributable to the end he was lining up behind.
My analysis is that PD is going to have a solid year. If he is in fact quicker and stronger than in times past, we should see more sacks and hurries from him. Regardless of his numbers though, his presence on the line is stabilizing and will help to keep opponents' rushing attack in check.
Having said all that, I'm not sold on PD being around much after next year. He faces the same problems that Renaldo Wynn did (a relatively hefty price tag for adequate but declining ability). Basically he's old and there is really no way around that. Father time will take his toll. But I expect PD to knock some heads around this season, or at least to occupy some O linemen and let our LBs knock some heads around.
So as to engender some discussion and so as to cast doubt on my statement regarding the unimportance of individual stats for D-linemen, I wanted to mention Chris Wilson. I believe that Wilson started four games last season in which he recorded 11 tackles and 4 sacks. Andre Carter started four times as many games (16) and got 43 tackes and 10.5 sacks. If you do the math, (4 x11=44; 4x4=16) Wilson's performance, projected over a full season of starts, equates to that of Carter, save with a greater sack ratio (especially considering the two he got in the playoffs which weren't counted). While it's true that Wilson played alot more downs than four starts would account for (which dilutes the comparison considerably), he is comparable to Carter mathematically. I'm not saying that Wilson will be PD's replacement or Carter's mirror image, but it's safe to say he is an underrated D-end and a potential sleeper on our roster. If it's between Wilson and Evans, I take the younger Wilson in a heartbeat, even at a skinny 240. It also provides a bit of comfort in the event that Carter or PD goes down and Earsmus is still gimpy.