They sort of need to be able to rollover that 15m salary in savings into 2022 because they really need it.
I think most people, though I do not think teams do this, look at cap savings wrong. They look at it purely on a year-to-year basis and see numbers moving on a purely year-to-year basis. Sticking with Atlanta I can use another example with a player who will not get cut in Matt Ryan. Matt Ryan has a 48 million dollar cap hit next year and cutting him only saves 8 on its face. BUT if you think of it in terms of money you have to pay out cutting him saves 24 in cap space as you will not have to pay that out but the bonus always has to be payed out, it is just a matter of when.
Now 24m for a starting QB for a year is absolutely worth it so he will be their starter next year, but that is in my eyes a more accurate way of looking at the cap. For Julio this means if they trade him they save the 15m that they need desperately for next years cap. They only have 33m over the next 2 years with which to build a team with people they are going to need to pay.
I mean there's two ways teams look at this... cap spend vs cash spend.
Cap spend is, in some ways, fictional. Like its a made up budget for the league. Its important, and teams have to adhere to it, but its not "real" in terms of money. It doesn't impact the profitability of a business.
Teams cut or trade players all the time for little or no cap savings, purely because it costs the business (i.e. cash) too much to keep them.
With Ryan, lets say they draft a QB this year. Obviously, they basically can't move Matt Ryan this year.
But in 2022, he's owed almost $24M in cash (between salaries and bonuses). I seriously doubt any owner is going to be willing to pay Matt Ryan $24M after they used the #4 overall pick on a QB. So they'll move on from him one way or another. It'll just depend on timing and how they can maneuver the cap to make it work. They may end up cutting him entirely and taking a $40M dead money cap hit, with only the $8M in savings. But if that's their only option, it wouldn't be surprising. And again... a lot of that dead money hit the business in prior years. For the profitability of the business, that's just a straight $24M in cash savings. Very material to an NFL franchise.
I agree Atlanta could use the cap space for next year, but there's also cap savings to be had for next year if they move Julio next year as opposed to this year. However, his trade value would likely be higher this year, which is probably the main motivator.
Ultimately, it kind of just depends on what Atlanta's "vision" for the next 2-3 years is. If you think you can become a contender, trading away good players probably doesn't make sense. Draft as well as you can and plug holes as cheaply as you can. If they think the time is "now" to start the beginning of the end of the Ryan/Julio era, then moving one this year and moving one next makes all the sense in the world.
I don't know how they have QBs in this draft valued or who they like/don't like. They're going to miss out on 3 of them, so it just depends on what's available. I would personally think any team would be happy to have Justin Fields, but it appears plenty disagree.