McCann, an SMU product, was released on Sept. 4 by the Cowboys before the start of the season. Philadelphia and Baltimore were interested in him after he was released.
The Ravens had problems in the return game, and Miller is someone that might help in the area.
The Cowboys have three cornerbacks on their roster and will use rookie Akwasi Owusu-Ansah at corner if necessary.
If the Cowboys can claim McCann off waivers, they'd have to cut someone on the active roster.
Fullback Deon Anderson and linebacker Jason Williams are possible candidates. Anderson wasn't allowed to practice on Wednesday with a knee injury, and Williams, last year's third-round pick, has struggled in the limited time he has played.