I heard this on a talk among GMs on the Sirius NFL station.

Because players are not required to get vaccinated, but are required to continue to take regular Covid tests (this is going to continue indefinitely), then teams MUST have an extra Kicker, Punter, and LS available because on game day, one might test positive. Then what?

So because it's not that hard to stash any one of those 3 on the PS, and they will practice and can be observed, then smart teams are adding several just in case.

The Rams are NOT adding these guys as true competition, but rather as insurance against a sudden positive Covid test.