The list the Arizona Cardinals have put together in their search for a defensive coordinator is getting whittled down.

Quickly.

The Cardinals requested permission to interview Pittsburgh Steelers linebackers coach Keith Butler and Kent Somers of the Arizona Republic reports that request has been denied. Butler has long been considered the heir apparent to Dick LeBeau in Pittsburgh and if LeBeau doesn’t retire after this season, he’s not expected to continue too much longer.

Ray Horton, the Steelers defensive backs coach, has multiple offers in play. He is expected to interview for the job and also has been offered a defensive backs job by the Dallas Cowboys, according to Jason La Canfora of NFL.com.

Per Somers, Arizona has also requested permission to interview Green Bay Packers linebackers coach Winston Moss, who is also the team’s assistant head coach. It’s not yet known if the Packers will grant him permission. Last year, they denied the Chicago Bears’ request to interview quarterback coach Tom Clements for an offensive coordinator role.

Pretty soon, we ought to know who is still in play for the ever patient Ken Whisenhunt.

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Brad Biggs covers the Bears for the Chicago Tribune