Arizona Cardinals defensive back Tyrann Mathieu was injured in Sunday's week 15 matchup between the Philadelphia Eagles and Arizona Cardinals.

The Cardinals hoped for the best however the injury looked pretty nasty as it was a non-contact knee injury. As it turns out Mathieu did indeed suffer a season ending torn right ACL putting a major cloud on the Cardinals victory over the Eagles. Mathieu is easily the best defensive back on this team and he also helps the rest of the secondary play better. Without him Patrick Peterson will be left to do all of the heavy lifting alone.

Mathieu was primarily the Cardinals slot defender and has been absolutely prolific. He has been a turnover machine as he racked up 5 interceptions on the season, 16 pass defenses, and a sack. Mathieu is Pro Football Focus's number 1 ranked cornerback by a mile and has easily been one of the best defensive backs of the year.

This is Mathieu's second knee injury in 3 years and his first was not that pretty either; in 2013 Mathieu suffered a torn left LCL and ACL. He will be significantly less effective coming off of this injury as he showed in 2014. This is a devastating blow for this Cardinals secondary with Super Bowl hopes.