According to the report, McClain will receive a base salary of $3 million and can earn another $1 million in incentives.
The New England Patriots also had interest in McClain.
McClain, 25, had 81 total tackles last season for the Cowboys. He also had two interceptions, one sack, three passes defended and one forced fumble.
He was the No. 8 overall pick in the 2010 draft and played three seasons with Oakland Raiders before being released in April 2013.
McClain signed with the Baltimore Ravens a week later but announced his retirement soon after and did not play the entire 2013 season.
Baltimore traded McClain to the Cowboys last July for a 2015 sixth-round pick.
- Scooby Axson