two ways to look at it IMO:
* if you're just contrasting base salary, by game, vs production and impact, then Nurk has provided decent-to-good value. But that's a really narrow way to look at everything
* coming into this season, Portland had played 176 counting games (regular & playoff) since Nurkic signed his contract. Nurkic had only played in 84 of those games...less than half. So, essentially double his salary to get an idea of how his salary stacks up when adjusted for injury. Has Nurkic been worth 24-25M a year? Nope
not only that, Portland has had to make roster moves because of Nurkic's lack of dependability. They paid Whiteside 27M last season because of Nurkic. They picked up Kanter this season although you can certainly argue that was a sound decision, with or without Nurkic. In a sense, Nurkic occupies two roster slots: his own and the replacement Portland needs when he goes down
the worry is that Nurkic just didn't start getting injured when he arrived in Portland. He missed 70 game in two years in Denver. By the time he comes back from the latest injury, he'll have played in less than half of the games he could have in 7 seasons. That's not good value, even at 'only' 13M/year. And the negative value extends to roster uncertainty because of this