This move is fascinating. The speculation monsters will have a field day trying to figure out all the possible ramifications that this move could represent. Here are just a few.
1. Sign and trade - the Pats would get an end of the round 3rd comp in 2021 just by letting Thuney walk as most of us expected. By doing it this way, even if they traded him for a 3rd rounder, it would be better than the comp 3rd PLUS a year earlier. Anything higher than a 3rd would be gravy.
2. Tom is gone - Ulimately they keep Thuney, Andrews comes back healthy, and the Pats have one of the better OL's in the league to surround Stidham or whatever Plan B QB is out there.
3. Marcus Cannon is gone - They offset some of the Thuney price tag with the 8 or 9MM they'd save by letting Cannon go and rely on one of the OL additions they made last season or Cajuste could come back and fit in. (Any word of the state of his leg issues?)
BOTTOM LINE: this move, one way or another, will have big ramifications on what the Pats eventually do. My best guess (at the moment) is #1