Let's say Hayward opts in, Kanter re-signs with the C's for 120% of his current contract and we use all our first round picks. Not the worst case scenario in terms of trying to avoid the tax, but it's pretty much close to it.
payroll in 2020-2021 (assuming we dump Poirier)
1. Kemba $34,379,100
2. Hayward $34,187,085
3. Brown $ 23,883,929
4. Smart $13,446,428
5. Tatum $9,897,120
6. Kanter $5,720,400
7. Theis $5,000,000
8. Langford $3,631,200
9. G. Williams $2,498,760
10. R. Williams $2,029,920
11. Semi $1,752,950
12. Edwards $1,517,981
13. Memphis pick (#17 at the moment) $3,123,960
14. Celtics pick (#26) $2,145,120
15. Bucks pick (#30) $2,040,480
-----------------------------------------
Yabu $1,039,080
Jackson $92,858
-----------------------------------------
SUM: $146,386,371
According to latest rumors, the tax line for 2020-2021 is projected at $138-$139 million.
In this scenario, we'd be around $7.3-$8.3 million above the tax line.