Quinn is signed through 2019. Cap hit is $11.4M in 2018 with under $1M dead cap if released or traded. Cap hit in 2019 is almost $13M with no dead cap.
Dead cap this year is $11.7M, so he is not tradeable until the season is over.
If he doesn't get productive he will be released or traded after the season. That is a lot of cap space to bring in a FA. I'm not sure how tradeable he is with that salary in 2018 and 2019, but there usually seems to be a team or two desperate for 4-3 DEs who can get after the QB - or have a history of getting after the QB.