What I like about Melton is that for a smallish DT he's a good run defender, so we could make him a three down 3-tech if needed. He will be hungry for those reps too, as this is a prove it deal if it happens.
But yeah, he had an ACL tear last year. It usually takes two seasons to fully recover and we saw last year what Clemons looked like coming off that injury. He lost a step and was basically just a league average player at an age where many pass rushers peak. Knee injuries are a pretty big deal for lineman on both offense and defense, especially defensive tackles who have to absorb so much force with their knees in the run game.
It's silly to expect an AP type recovery for Melton, but if he did, he'd be a very nice addition on a 1 year deal for a moderate amount of money.
I have no such worries about Allen. Last offseason I thought we really missed out by failing to sign John Abraham to the super-cheap deal he settled for. He had yet another double digit sacks season last year. Of course he would, he's old but the athleticism is still there. Jared Allen is a pretty similar guy, except he's almost four years younger than Abraham is. I could see Seattle signing Allen to a 4 year deal and he could play well enough that cutting him in year 3 could be a really tough call, whereas with Melton, even if we get him, its only going to be for one year. His ACL mending year.
Basically, it comes down to signing a one year guy who will probably be okay, versus making a medium-term investment in a really good player. If Seattle thinks they can budget a few years of Allen in while keeping Sherm/Earl/Wilson, I would call that a no-brainer for them.
