Jared McCain has played 37 games in his NBA career and tore his meniscus and UCL between the first 23 and the most recent 14. So there are multiple reasons McCain's inconsistent production in year two (he's shooting 38 percent from the field right now) are no cause for concern.
It feels like a lifetime ago that the Sixers drafted McCain because of the chaos that has ensued since then, so it's easy to forget that he's missed more games than he's played in his NBA tenure. He should still be allowed to hit the "rookie wall," which usually comes around halfway through a player's first season — which McCain basically is right now.