It's worth remembering that GMBM and Trotz have both reiterated that they see John Carlson as a number 1D - it speaks volumes that in the final regular season Anaheim game, where they boxed their most important players (Ovi, Backstrom, Holtby), Carly and Orpik were both boxed and Niskanen and Alzner not only dressed, but overused as usual. If they didn't see Orpik as a top-4 player for them who they couldn't afford not to lose to injury, they would have played him and given Alzner fewer minutes. Don't underestimate how much they continue to value Orpik - and to an extent, with good reason.
If they do feel the need to move Orpik to the third pairing this coming season (I don't see that happening) they'll either need to bring someone new into the fold to partner with Carly, or break up their elite shutdown pair Alzner-Niskanen. Orlov has shown absolutely nothing to suggest he deserves first pairing minutes, and hasn't yet demonstrated he's good enough at stay-at-home hockey to reliably cover for our best offensive defenceman.
GMBM talking of Orlov potentially being able to step up and take some of Orpik's minutes doesn't mean partnering Orly full time with Carlson or Niskanen. I suspect they'll be more keen to get the third pairing of Orlov-Schmidt-Chorney bigger minutes in the regular season so they can rely on them a little more and not have to overuse Alzner, Niskanen and Carlson.
The Orlov-Schmidt pairing did a great job as a second pair while Orpik and Carlson were out. I think part of the problem is when Orpik and (eventually) Carlson returned those two really needed bigger minutes in order to get them ready for the playoffs and wear off the rust from injury - and at about the same time Orlov started trying to step up his offense in riskier ways to make an impact (having actually been quite reliable while on second pair duties) and Schmidt completely lost his rhythm when he got injured for a couple of games and started being scratched as part of the flawed Chorney/Schmidt/Orlov rotation.
My bet, though, is Orlov gets benched at points this coming season. For most of the year, he deserved to be a lot more than Schmidt and Chorney did.