Watch Now: Interest in Antonio Brown Picking Up (2:27)

Despite a bizarre and unprecedented September that included him being embroiled in an sexual assault civil suit and getting quickly released by two teams, league sources said that numerous teams are keeping a close eye on Antonio Brown, and a return to the NFL after the trade deadline would not come as a surprise.

Brown managed to leave under poor terms with the Raiders and Patriots, including lashing out at owners and others on social media and filing numerous grievances to try to recoup $30 million million in lost salary. He has kept a lower profile in recent weeks, however, and there are a handful of contending teams fairly desperate and motivated to upgrade at the receiver spot, and Brown's name has come up in internal discussions in several personnel meetings, sources said.

Receiver is a position of significant attention ahead of the trade deadline, now less than two weeks away, and with several blockbusters already completed since the summer, contact between teams is high. Bengals former Pro Bowler A.J. Green is the most coveted option, with other clubs hopeful the winless club reverses course and opts to deal the pending free agent this month. Denver's Emmanuel Sanders, another pending free agent, is drawing heavy interest for the second straight year, but the Broncos have recently turned their season around. Larry Fitzgerald has rebuffed any possibilities to leave Arizona in the past, and that's not expected to change now.

The slumping Falcons could shed some salary by dealing veteran Mohamed Sanu, and several general managers I spoke to believe that will happen by the deadline. The Dolphins may find a taker for former first-round pick Devante Parker, who has yet to really develop there.

Once the deadline passes, expect interest to pick up for Brown, who, despite still being the focus of a league investigation into the various allegations against him, made an immediate impact in the one game he played in New England and would be a substantial upgrade over many starting receivers, assuming he manages to actually stay on a roster. Besides the Patriots, the 49ers, Saints, Ravens, Colts and Packers are contending teams that could benefit by the addition of another pass catching option.

Of course, given the extremes of his behavior and the seriousness of the allegations against him, signing Brown would require ownership approval. And there is a strong sense in many front offices that bringing in Brown would be more trouble than it's worth, but it only takes one team to sign him to a bargain deal for the remainder of the season, and that is increasingly looking like a real possibility.