There is some understandable confusion with regards to how this stuff works, so I figured I’d spell it all out for you.
There are two different times in a season when a player can be waived using the stretch provision. You can waive them between July 1st and August 31st and then you can waive them between September 1st and June 30th.
If you waive them during that July 1st/August 31st period, then you split the remaining years of the player’s contract over a period of two times the remaining years plus one. In the case of, say, Joakim Noah, then had the Knicks waived him back in August, he would have counted as $7,565,000 a year against the cap for each of the next five seasons (the two remaining seasons on his deal times two plus one, so five years).
The Knicks, though, would only open up minimal cap space this season had they done this (essentially less than they would have to spend using the mid-level exception had they not gone under the cap), so they did not do that.
Instead, the Knicks waited until just the other day to waive Noah and use the stretch provision on him.
If you waive a player between September 1st and June 30th, you pay them their normal salary in the current season and then the remaining years on the contract after that are stretched out over twice the remaining years, plus one.
This means that the Knicks pay Noah his entire salary this season and then spread out the remaining $19,295,000 over three years, which equals $6,431,666 a year over the next three years.
You might notice, then, that that means had the Knicks waited until next offseason, when they knew whether a free agent would sign with them or not, they would have been able to waive Noah then and then use the stretch provision to split the $19,295,000 over three seasons, which would end up in exactly the same spot as they are now, financially.
Of course, teams can also work out different terms with the player where the player can give up more money so that they can become a free agent. That obviously did not happen here.
In simplest terms, there is no financial benefit for next offeason for the Knicks waiving Noah and using the stretch provision on him now. Even if they think that they are a place where free agents would like to sign next July, they could have waived Noah then and achieved the same benefit.
In other words, the only benefit to the Knicks by doing this now is opening up a roster spot for a player. I’ll leave it up to you to debate whether that benefit is worth this move.