This followed a trend in recent weeks where SmackDown's General Manger has either not been part of the show or been severely downplayed. He's seen uninterested and aloof. Of course, that's the way Bryan has been scripted to act, though it hints on some real-life disappointment Bryan has felt while failing to obtain medical clearance from WWE to perform again.
However, the reason he wasn't at Fastlane has been revealed and it has nothing to do with storyline or creative frustration.
Bryan was not able to attend the show because he was attending his cousin's wedding alongside wife Brie Bella. Bella sent out a post on Instagram that revealed as much.
You'll note the date on the photo strip is March 10th, which was Saturday, so it wasn't entirely impossible for Bryan to have been flown into the show. That said, he certainly would have been under a time crunch and some travel pressure, so WWE clearly must have given him permission to the miss the show to attend the family function.
Bryan's direction heading into WrestleMania remains under lock and key. Rumors persisted for months that he may be involved in some kind of match involving himself, Shane McMahon, Kevin Owens, and Sami Zayn. The way that the story has been built up on television, that match would make tons of sense, though would require medical clearance for Bryan. That's not looking likely at this point, and any chance of it happening is certainly on life support. Even so, if Bryan were to wrestle again for WWE, it might be likely that they would save such a big moment for a different show as the WWE WrestleMania card is already becoming quite stacked.