I don't think we can conclude quite yet that Nelson is washed up. He looks sluggish in his breaks, but it's worth noting on that deep throw INT against Carolina Nelson had a couple of steps on the defenders but Rodgers was a bit late and under threw him. It could be a case where he's dinged up in such a way that it impacts cuts but not straight line running.
That said, I don't think his 5th. gear is quite what it was pre-ACL. We just don't know if he's been soldiering through or if this is as good as it's going to get for him going forward.
Nelson, Matthews, Cobb all have contracts ending in 2018 and in all 3 cases there's a significant increase in cap savings and/or decrease in dead cap were ways to be parted. It's all fine and good to make that observation, but when you get to the corollary consideration, "who else ya got?", there are no clear answers.