The gist of what I saw a lot of yesterday is he's good not top tier, and the contract situation. This is part of the article that seemed to be making the rounds yesterday:
"Many around the league believed Dallas overpaid, based largely on the belief that teams don’t view Porter as a top-tier corner. The Cowboys have a strong recent history of overpaying for talent: a fourth for Trey Lance, a fourth for receiver Jonathan Mingo, a fifth for Joe Milton, a fourth for Rashan Gary.
“They were bidding against themselves for Porter,” says one executive with a team that was erroneously tied to trading for the cornerback. "