Mathieu is coming off a season in which he had 66 tackles and two interceptions for the Cardinals.
"I've never made a secret that Tyrann has always had a special place in my heart and always will", Cardinals general manager Steve Keim said on Wednesday.
The 25-year-old was a 2013 third-round pick, and he has 11 interceptions and four sacks in 66 games.
Mathieu signed a five-year, $62.5 million contract in 2016 with the Cardinals.
The deal is worth $7 million, according to Schefter.
Not long ago, he inked a new deal with the Arizona Cardinals, but with Arizona seemingly in rebuild mode, the team chose to release the honey badger.
"Lets go bro!" Mathieu tweeted in response to Watt.
"Y'all see what's going on man!"
Mathieu can line up at cornerback or safety, matching up against pass catchers with diverse skillsets and body types.
The Texans, assuming quarterback Deshaun Watson is healthy again after tearing his ACL, have a chance to be good.