We can discuss whether Harrison was ever healthy, is losing his skill set, was getting stronger at the end of the year, etc until the cows come home. If, and by all estimation, Worilds is a better option based on pass rushing ability and setting the edge at this stage of his career than Harrison was when he took over for Porter, then why are the Steelers even talking to Harrison? They should cut him and never have even started negotiations, but they didn't.
I have to believe that while rushing the passer and setting the edge are the primary responsibilities the Steelers are viewing the other facets of the position more heavily than us fans are doing, otherwise, Harrison would simply be a cap casualty without even talking to him, IMO. Worilds would be able to rush the passer and set the edge nearly as well as Harrison and over time probably just as well. Since, they are still trying to resign Harrison I have to believe the front office doesn't think that Worilds is ready for a full time gig.
"Before you can win a game, you have to not lose it." -- Chuck Noll
I watched every quarter of every game this year. As it pertains to Harrison, I definitely noticed how slow and unathletic he seemed running around the field. Toward the end of the year, I (as someone who really watches him and hangs his hopes on Harrison) saw a SLIGHT uptick in terms of his game. Slight. I didn't see the old Harrison, or anything near. I didn't see him rocking back OT's, or dipping his shoulder. (In fact, I saw them drop him more than anything else, which says a lot in/of itself.)
Point being, I don't really know what we get with him. If you asked me straight up, I'd say that he is washed up, painful as it may be to say.