I think the question is, does Leonsis let them spend the money. No way the team would be forced to lose the player -and- not have the cap space come available. Well, it's the NHL so who knows, but at least that's how I think it works.
Here are the salary cap implications of Backstrom's situation as I understand them.
Once Backstrom goes on LTIR, as I assume he will soon, his $9.2 million cap hit becomes an exemption amount that the Caps can spend over the salary cap, with Backstrom's $9.2 million counted toward total salary obligations.
I think that people here are right. Backstrom isn't going to retire because of all that money, and the Caps' organizational statement that they support Backstrom in this soul-searching departure means that they are fully supportive of paying him, probably thinking of it as a thank-you payment for honorable service.
Backstrom signed his current contract at age 33; i.e., before age 35. That means that IF he were to retire now, his contract AAV would be wiped off the books for salary cap purposes. The rule is that if a player signs a contract at age 35+ and then retires, that AAV counts towards the team's salary cap for the duration of the period covered by the contract.
So whether Backstrom retires or he doesn't, the Caps get $9.2 million of cap relief from his absence unless he were to return to the active roster. IF that were to happen at some point, then the Caps would have to return to compliance with the salary cap with Backstrom's cap hit included.
As a tiny answer to Mick's question, IF there is even a shred of a chance that Backstrom returns to duty, the Caps COULDN'T spend his salary cap exemption money willy-nilly right now, because players they would acquire using the exemption would have to be jettisoned, or something else major would have to happen, in order to get back down to the salary cap upon Backstrom's return. However, let's say that the Caps don't spend very much of Backstrom's exemption now or for the next few months. All they do is juggling with relatively inexpensive Hershey callus that can be sent down. Now let's say the trading deadline approaches, Backstrom is still out and is nowhere near returning, which means he wouldn't return until the playoffs -- if ever. The Caps could then load up on players at the deadline if they were in the playoff hunt or something, with salaries up to the $9.2 million exemption amount.
I suspect the real outcome of this situation is that Backstrom will never return and the Caps have that $9.2 million to play with for the next two seasons. It will be like the Tampa Bay situation, and there is nothing to fault the Caps for ethically, because Backstrom made a good-faith effort to return to play, and actually did play some games and a few this year, until he just couldn't deal with his condition any more. This isn't like where Tampa held Kucherov out until the playoffs to circumvent the cap and then voila, he returned good as new, when there was a lot of suspicion that he physically could have returned earlier, but Tampa loaded up with replacement players that would have had them in salary cap hell had Kucherov returned during the regular season.