He doesn't need both John Wallace and Cedric Ceballos. Nor does he need both Michael Curry and Jud Buechler. He does, however, need a rugged, scrappy big man to deliver energy and muscle off the bench. A quick aside here about Ceballos. He is not in Irvine's doghouse.
Players earn playing time.
Coaches don't dictate playing time. Players don't fall in and out of favor. If you work hard defensively and you play together, then you play. The Pistons probably should think about deactivating Ceballos or Curry, at least for five to 10 games, and determine whether Cardinal can make an impact. You know what those two veterans bring.