While NFL free agency kicks off at 4 p.m. ET on Wednesday, free agents aren't the only players who will be changing teams at that time. Trades involving players under contract for 2019 won't become official until then either.
This means that trades that have previously been agreed to can still be nixed. Yes, even the one that should send Antonio Brown to the Oakland Raiders.
Gerry DulacSteelers source emphasizes AB trade is agreement only and “it’s never over till it’s over.”
Most likely, though, the Brown trade will go through, as will the Olivier Vernon-Kevin Zeitler swap and the trade sending Joe Flacco to the Denver Broncos.