Sign Damon Harrison: He's the top free-agent nose tackle on the market, but he's a two-down player, so that will limit his value. If the Redskins can add him for $4 million per year, they'd have a player in his prime who has been durable and excellent versus the run.
On re-signing Will Blackmon and/or Terrance Knighton: I've written many times, starting in mid-January, that Knighton was not part of their plans (not saying that to admonish, but to point out that what I've heard has remained consistent). And Knighton himself even said on Sirius XM radio earlier this week that he had not heard from the Redskins. There are options in free agency and the draft to replace him. I think the weight issue bothered the team; they felt he could be more productive at a lesser weight.
It's also possible the Texans would bring in Griffin without any guarantee of playing time - in fact, that could be the situation for RG3 where ever he goes. Despite his fame and the incredible rookie season of 2012, the reality with Griffin is now an oft-injured QB who didn't take a single snap in 2015 and looked mediocre in 2014.
Rewind: Morris' came into the year on precipitous slide that followed his breakout rookie season in 2012. In 2013 and again in 2014 both his rushing yards and average per carry dropped. He was unable to reverse the decline in 2015, posting new career lows in rushing yards with 752 and yards per carry at 3.7. Despite his struggles, he started all 16 games just has he has every year starting Week 1 in his rookie season.