Week 1 fantasy football rankings are always difficult, as it's tough to know what to truly expect of players in new situations and just how favorable/unfavorable a matchup is. When it comes to wide receiver rankings, it's even tougher to evaluate guys because of the boom-or-bust nature of the position.
We're not taking too many chances at the very top, but matchups do come into play, both unfavorable (Jordy Nelson, Davante Adams vs. Seattle) and favorable (Stefon Diggs, Adam Thielen vs. New Orleans). Ultimately, both Nelson and Adams are probably going to start if you drafted them, but you should at least explore your options.