My recollection of most of what he did well on in preseason was mostly just straight deep routes. And frankly, it's preseason. Apparently Simi Fehnoko of the Chargers was #2 in preseason with 170 yards. Simi Fehnoko has a total of 3 catches for 61 yards this year for the Chargers with no TDs. So preseason performance doesn't always translate.
And yes, I think a lot of it has to do with him messing up in practice and Kubiak believing that you have to practice well to play well when it counts.
Anyway, I think Perry has some skills. Mostly height and the ability to find soft spots in zones. That may be enough for Carmichael but it isn't enough for Kubiak. And it's also a skill that works for a team that runs a lot of 3 and 4 WR sets more than a team like the Saints now that run a lot of 2 WR sets.
Anway, I'd bring him back in on the 53 after this game since we don't have many options otherwise, but I honestly don't have a lot of hope that he's ever going to be much more than a #4 WR and possible red zone guy. Which obviously has it's advantages, but might not be worth keeping over other players that can do more. Part of his problem is that he doesn't play special teams and you have to do that to make it as a #4 to #6 WR in the NFL.