If you harbour any hope of a big name free agent in either 2017 or 18 then you don't make this deal
it wouldn't affect much in 2017 because you just sign Noel after you sign whatever free agent you land. It would alter 2018 obviously because Noel would have a much larger contract than Smart's cap hold.
Not quite sure that is true.
If we pickup the team options for Rozier and Hunter and then extend QOs to Noel and KO then our salary entering FA will be $77,144,125 I believe. The QOs for Noel and KO have a higher cap hold than their actual values, for instance Noel has a QO of $5,848,910 but the cap hold is $10,961,255. The CBA FAQ has more info on why this is.
With a projected salary cap of $102m that leaves us with $24,855,875 of cap room. The max salaries for next summer are:
0-6 years: $22.1m
7-9 years:$26.5m
10+ years: $31m
So to sign someone like Griffin or Hayward we would need to move a contract to create the cap space. Rozier would be the smallest contract that would make enough space, letting go of Hunter wouldn't be enough. We'd also have to waive the rights to Jackson, Zeller and Mickey as well as our FAs.
It's not the biggest concern in the world because we could move a player for a pick if we had to but it's something to think about
Edit: I forgot about the cap holds for Yab and Zizic + our pick this year so actually there's a lot more cap space we'd have to clear. Probably Bradley and Rozier kind of salary. Much less feasible now
depends on the average salary, Noel's cap hold might only be 8.6 million (200% as opposed to 250%). Either way his hold is worth 4.3 to 6.5 more than Smart, so that is the cost of having Noel vs. Smart.
So Noel and KO would at most be 21.5 of salary. 27.7 from Horford, 26.9 from Bradley, Crowder, Thomas, and Brown. 2 from Rozier and about 3 from Zizic and Yab. Plus let's call it 5 million from the BKN pick.
So without Noel and KO that is about 64.6. Now put in KO and Smart and Boston doesn't have enough for a max contract (less than 7 years is probably looking at 24 million to start) and that is with giving up the rights to Johnson, Jerekbo, Zeller, Mickey, Jackson, and Hunter, something I'm not sure Boston would really want to do.
So when I say having Noel vs. Smart won't change much, it is because Boston doesn't have room for a max free agent anyway unless it gives up valuable players like KO, Smart, etc.
I personally believe going from Smart to Noel is worth having 4-6.5 less cap room next summer when Boston doesn't have room for a max contract to begin with.