In an interview with Forbes, Senior Game Designer Patrick Scarborough revealed that the Revival Catalyst will be available during the first week of Season 3, however, you will only gain a charge every two weeks instead of every week.
Full Forbes Interview
In hindsight, that was just not really in sync with how free the upgrade system felt immediately — so there were two systems that were talking past one another.
We wanted you to feel the kind of tension and excitement of unlocking your tier pieces, but when everyone was rocketing up in item level so fast, they just didn't feel like they mixed.
Newman: So what are you doing for this season?
Scarborough: We're going to be moving to a system where we unlock the Catalyst at week one. It is available, but you are going to earn charges more slowly, so every two weeks instead of every one.
There are a few other tweaking and moving of numbers to make that make sense.
What this effectively means is that if you are a non-raider, you are not going to be nearly as disadvantaged as you've been before. You're going to be starting to get pieces from the jump, though you will have to wait two weeks for your next one, and two weeks for your next one.
The point at which most people would get their four-piece does not change, but the point at which you can start collecting them, especially if you're a non-raider, starts sooner..