middle guard

noun3

1. •
   A defensive player positioned in the middle of the pitch, opposite the offensive center and between the defensive tackles; the nose guard.

   • It allows the middle guard of the defense to roam, and with the combined efforts of his teammates he will emerge your leading tackler game in and out. — 1956
2. •
   (rare) The guard.
3. •
   (rare) One between the new guard and the old guard.