Overall usage of zone defenses — schemes that call for defenders to guard a specific area of space rather than an opposing player — is up 50 percent from last season, according to Synergy Sports data. The increase per possession is 10.8 percent, according to data provided to N.B.A. teams by Second Spectrum. A leaguewide average of 2.3 zone possessions per game remains modest, but the rise Carlisle referenced is more tangibly reflected by the number of teams regarded as regular zone practitioners.