My take is that as long as the 3 players are practicing the week following the pre-season opener at the Giants, they should be able to hit the ground running when the regular season begins.
D.J. Reader very likely will begin the regular season on the PUP list. Knowing firsthand the difficulty involved in recovering from a Torn Quad Tendon to function normally in everyday life, I understand why D.J. Reader is smart not to rush the recovery process for him to return play DT/NT in the NFL.