To put it simply, the 2019 Notre Dame football defense will be one to watch. There is amazing depth at certain positions (defensive end), while there is lack of experience and depth at others (cornerback, linebacker).
It makes for what should be a fun defense to watch at times, with plenty of potential breakout candidates. Jack Lamb, Shayne Simon and Houston Griffith are all names that could make a huge impact come this fall.
However, none of those three players are considered to be irreplaceable just yet — by my standards anyways.
To me, irreplaceable means the defense is going to crumble without that certain player in the lineup.