It's usually not a great idea to go wild with the waiver wire before the NFL regular season has even begun. However, sometimes it's a necessity.
Oftentimes, an early fantasy draft can leave managers with a player they no longer want or who won't be available. For example, the early training-camp buzz on New England Patriots running back Damien Harris likely led several managers to draft him. However, New England recently placed him on injured reserve with a hand injury,
Harris will be out for at least the first three weeks of the season, and if that leaves you short a running back, the waiver wire is the first place you'll turn.