It's never too early to start streaming. Gamers who had the misfortune of drafting Andrew Luck or Lamar Miller are already looking for roster help. Additionally, those riding out the holdout of Melvin Gordon could be looking for an early-season option, too. There are also gamers who've made unbalanced player swaps, opening up a streaming spot on their roster.
Regardless of the motivation for turning to the waiver wire/free agent pool, this is the place to find streaming options -- even for gamers in leagues as large as 14- or 16-team formats.