Andrew Pullin, IMHO, is in the "may be exposed, at some risk" category. He has potential, but can he stick on a 25-man roster for a full season, as an outfielder? Don't know; if it were me, I might well protect him, but I don't see him as certainly on the Phils' list.
Cam Perkins? I don't protect him, and I don't think the Phils do either. There are reasons whey he never got called up this season, and why Jimmy Paredes was acquired instead.
Carlos Tocci? See Andrew Pullin, with a lot more uncertainty. I really don't see anybody burying Tocci on a major-league roster for a season, at this point. We're talking about a .693 OPS in single-A. If he plays well in AA, then sure, he would be at risk, but I see that as a year from now, not this winter. The Phils may disagree; I don't know.
The guys you cut are the guys you're likely going to lose anyway, because you're going to have to expose them to waivers at some point - the guys who won't spend the season on the Active Roster, and who don't have options remaining. That's Buchanan, Garcia, Mariot, Ruf. In the Phils' case, all four of these guys have served their seven-year minor-league purgatory; if they're waived, and not claimed by another team and added to that team's 40-man roster, they are eligible for minor-league free agency. So the long and short is, if any of these guys is not kept on the 25-man roster all season in 2017, that guy is likely gone, gone, gone. Given that none of them has really earned a roster spot...might as well just let 'em go now, as later.