Some background info-- Derrick nominated Donny and Christine with the hopes that they would lose the battle of the block. Christine threw it, and cheated by handing puzzle pieces (or whatever they were) to Caleb and Cody. However, beastmodebeard still beat all three of them and achieved safety for the week.
Veto competition-- Frankie won. (Puke). There's a lot of speculation as to what he will do with the veto. He's telling the entire house besides Zach and Donny that he's going to backdoor Zach (and he's telling the entire house in an extremely obscene way). There's speculation that he MIGHT backdoor Derrick instead, as for a few comments made previous to the veto competition to Donny and to Zach (I.e telling Donny that Derrick has to go this week, telling Zach that he has to win HoH next week). Personally, I'm not completely sure. My gut is telling me that the comments Frankie are making are SO over the top and cruel that he must be just blowing smoke in order to really blindside Derrick, but then again he could just really be terrible at Big Brother and an awful person.
As of right now, it's either Derrick or Zach that is going to be backdoored.
IF Zach goes up, he will be evicted by everyone except for Donny.
IF Derrick goes up: Christine, Donny, and Zach will evict Derrick. Because they only need three votes (5 people are voting this week) he will be evicted.
Dream scenario: Derrick goes to jury, Hayden or Nicole (preferably Hayden just because he's strong as fuck) come back and side with Donny / Zach.
I don't think Frankie explicitly said he was going to backdoor Derrick pre-veto. He just mentioned to Donny that he had something "big" planned. And I'm pretty sure that "big thing" he had planned was just backdooring Zach, which I feared.