Everybody mentions the loss of Clemons but Jason Jones was almost as big of a loss. We lost our best outside rusher and our best inside rusher. There's also a good chance they won't be a factor for us next year.
Irvin, as a rookie, was reasonably effective when Clemons and Jones were also drawing attention. With those guys out, and him having to play more snaps and a play a different position, it's probably asking too much to have him out there as the only real pass rusher.
The Seahawks need to bring in at least two good pass rushers next year, preferably via free agency, since it usually takes a year or two for d-lineman to be effective.