Woah, this slipped my radar. Looks like "Someday" leaked about two days ago...
My guess is that this is a song off the band's upcoming album Beacon (due September 3rd). In fact, I'd venture to go so far as to say this'll be track 5!
Dry information aside, I'm actually finding this track a touch disappointing. The first single "Sleep Alone" was promising, but on "Someday" I feel that the band has gone a somewhat dry direction. Seriously...their technical ability far exceeds the stale chord progression and harmony here. Can't win them all, I suppose.
To be fair, this is an official single. Perhaps it fits better inline with the rest of the album?