Yes, it’s true that the Patriots wouldn’t have signed receiver Antonio Brown if they’d known about the lawsuit that was filed one day after his contract was signed. Ian Rapoport of the NFL reported it on Sunday morning, and PFT has confirmed it.
As if it needed confirmation. Or reporting. What NFL team would have signed Brown in the immediate aftermath of the filing of a lawsuit accusing him of sexual assault and rape? At a minimum, the Patriots and any other team would have investigated the situation before signing Brown -- especially with his accuser clearly willing to cooperate.
Everything changes when the lawsuit arrives after the contract is signed. Civil lawsuits are filed (or at least threatened) against players all the time. Firing a player based solely on uninvestigated and uncorroborated civil allegations would set a horrible precedent, for the Patriots or any other sports organization.
This doesn’t mean Brown is in the clear. The findings of the NFL’s formal investigation, the findings of any informal investigation in which the Patriots may engage, and/or the potential filing of criminal charges (the local district attorney has said his office will look into the incident that allegedly occurred in Pittsburgh) could prompt the Patriots to eventually sever ties with Brown.
Until that happens, Brown remains a member of the team. As he would be for any NFL team that signed him (and gave him a $9 million signing bonus) one day before finding out that the lawsuit against Brown was filed.