The phrase "cannot be played off the court" has been previously mentioned for players who are so good on one particular side of the court that they can fit with any lineup. For example, P.J. Tucker, even more as he gets older, has gone games without scoring a single point but still stays on the court because of what he brings on the defensive end. It's not common, especially in today's NBA, to have a player who can change a game so much on the defensive end that their offense is not needed to win a game.
That statement was commonly mentioned with Jabari Smith Jr.