NFL.com's Adam Schefter reports that new Detroit Lions head coach Jim Schwartz received permission to interview Kansas City Chiefs defensive coordinator Gunther Cunningham, who worked with him on the Tennessee Titans' staff from 2001 to 2003. One league source mentioned that Cunningham, whose job security in Kansas City might be in question, is expected to be hired in Detroit. Cunningham was one of the first coaches that Schwartz contacted. Should Cunningham be hired, he could become Schwartz's defensive coordinator with the Lions, working under him in the same way he did for three seasons when he was the Titans' linebackers coach and Schwartz was the defensive coordinator. ... Schefter also reports that Dallas Cowboys offensive coordinator Jason Garrett continues to be a strong pick to fill the head coaching vacancy for the St. Louis Rams. Garrett and his wife returned to Dallas from St. Louis on Saturday. Other candidates for the job include Baltimore Ravens defensive coordinator Rex Ryan and Minnesota Vikings defensive coordinator Leslie Frazier.