Morton wasn't a free agent, the Phillies traded for him. And nobody cares what he did before 2017 anymore. But the narrative on him is that he was already showing a big improvement in his stuff in 2016 before the injury, which he then unlocked with the help of the Astros analytics while staying healthy. In any case, what you are selling with the comparison is Morton's playoff performance and his 2017 season. But Chatwood still put up more WAR than Morton last year so what you are really selling is, if you put Chatwood in the right park with the right coaching, he'll be a 3-4 WAR guy rather than a 2.0 WAR guy, just as Morton went from a 0 WAR guy to 1.8. He's also shown increased velocity (like Morton). Doesn't make the comparison true, but that's what you're selling, and if it's a seller's market for the three best non QO pitchers, teams will be buying.
Especially since Chatwood is young. Given that, I gotta think he ends up with the surprise deal of free agency, MLBTR had him listed as the 6th-best pitcher with a $20 million two-year deal but I think he's ahead of Cashner, and now that the QOs are out there he can probably get a four-year deal unless teams are still wary of his health (he had TJ in 2015, missed some time last year for other thing). Like, Jake Arrieta is better than Tyler Chatwood but will 35 year-old Arrieta be better than 31 year-old Chatwood?