Lowe is presumably taking Drummond's entire career into account. Andre has always been a poor defender, and he's perennially lagged far behind his similarly-paid contemporaries among traditional centers in that capacity. It isn't native to this season. This isn't even his worst defensive season as a starter. And his best defensive season as a starter saw him achieve mere mediocrity, whereas the likes of Adams, Capela, Gobert, Whiteside, Jordan, et al were all in the league's elite echelons in defensive efficiency.

Lowe rightly notes that Andre isn't worth his salary without major plus defense. And that's true. Andre isn't a major plus defender, or a plus defender at all, but most often quite the opposite.