so like a mesh on the lower part of the cage over the mouth. Up top you'd have clear visor, then below that some kind of N95 material. While it would still let you suck contaminated air up from below the mask and into your mouth - it might cut down on the spittle that flies out as you grunt, yell, etc. Especially for lineman who likely trade lots of spit every game.

At least, that's how i would see it. Players wearing an actual mask doesn't seem workable because of the reduced air intake.