The date used to be two weeks after the NFL draft. But with the new CBA in effect for the 2020 season, any unrestricted free agent who now signs with an NFL team will not count in the compensatory formula. The player will not count as a loss for their previous team, nor will they count as a gain for their new team.
Why is this important to NFL teams, particularly the Steelers? If there is a free urgent still on the market which the Steelers give a qualifying offer, it will not affect the compensatory formula for the 2021 draft.