Robinson's gone. Now somebody has to actually play.

The Knicks opened training camp this week with Karl-Anthony Towns as their only proven frontcourt piece, which is a strange place for a defending champion to be. Mitchell Robinson — 8.3 rebounds a game, 69.6% from the field last season — took a three-year, $47.4 million deal to Boston in July, and the market gave New York nothing comparable in return. The Moussa Cisse offer sheet was the aggressive swing, two years at $4.7 million, and Dallas matched it within 48 hours. That door closed fast.

What's left is Andre Drummond on a one-year, $3.9 million deal, James Wiseman on a training camp contract, and Bruce Brown in the mix as well. Drummond is a known quantity — a veteran big who can rebound and finish around the rim, but a different player than Robinson in terms of rim protection and energy off the bench. Wiseman is the longer shot, a former top pick whose NBA career has never quite matched the draft-night billing. Camp will tell us something about where he is.

Towns can carry the frontcourt offensively — 19.5 points and 11.1 rebounds last season — but he's one foul trouble situation, one minor injury, away from exposing exactly how thin this depth chart runs. My read is that Drummond wins the starting job beside him and holds it, but the margin between him and genuine nothing is uncomfortably small for a team that just won a title and now faces Philadelphia's new-look roster in the East.