You can protect anybody who you're willing to put on the 40 man roster. If Gaub and Parker were put on the 40 man in order to be called up in September, they would be protected. But that would also take 2 of the available spots on the 40 man for other players that might need to be protected before the rule 5 draft. There's no separate list for Rule 5. At the time of the Rule 5 draft, anybody who's on the 40 man roster is protected. Anybody who hasn't had enough minor league experience is also protected. Everybody else who has been in the minors for long enough is eligible to be picked. Keep in mind, by the time the draft rolls around, there will be others off the 40 man, such as Johnson, Heilman, Gregg, Chad Fox, Cotts, and hopefully Miles.