Does Dak "have to sign" the tag? What has to happen until he hits the open market and can talk to other teams?
Dak doesn’t have to sign the tender (tag). See LeVeon Bell from a few years ago. However, he can’t play for or get paid by Dallas or anyone else until he signs it, or it gets rescinded in exchange for a long term deal from Dallas. The franchise tag is essentially a one year protection that a franchise can place on a player, and they may use that twice for the exclusive tag and a third time for a non-exclusive tag. A year is counted towards that by the player signing the tender and playing in enough games to accrue a full NFL season (player has to be signed and active by Week 9 or 10 I think to accrue a season).
So the rub is that Dak can choose not to play at all under the tag in 2020, but then Dallas can still tag him two more times since he didn’t sign the previous tender. And they can tag him every single year infinitely until he actually plays two seasons under it, if they choose. Therefore, Dak’s max leverage can be applied by signing the tender and becoming active, but not doing so until Week 9 or 10. This would destroy any playoff chances the Cowboys have, still get him about $17 million (over 4x his career earnings to this point), and count as one of the two years that Dallas could apply the exclusive tag. At that point, Jerry can tag him again in 2021 (in which case that would be his last year in Dallas in just about any scenario), give him his long term deal he’s asking for, or let him walk to the highest bidder.