Though Whisenhunt had the grace to wait until the sting of their Super Bowl loss had subsided a little before making the request, according to Jason La Canfora of the NFL Network, the organisation requested permission to interview Butler shortly before the news broke.
La Canfora cited sources who repeated their earlier indication that the Steelers were not planning to block the request, and that Butler would accept the job, if offered it.
Numerous other reports continue to confirm that Butler is still at the top of Coach Whisenhunt's wish list, and, barring any major blow-up during the interview process, Butler will be offered the position.
Though Butler was believed to be the successor to Steelers defensive coordinator, Dick LeBeau, indications that LeBeau, 73, will return for at least one more season mean that Butler will likely accept the coordinator position in Phoenix instead.
Butler, an experienced linebackers coach, would bring great energy to the Cardinals defense, which, in spite of talent, looked regularly flat throughout the 2010 season.
A great judge of talent, he would also help woo potential outside linebackers—the Cardinals' single biggest need outside of a quarterback—to the franchise.
Though nothing is set in stone yet—LeBeau could yet surprise everyone and retire, following the Steelers loss on Sunday—Butler now appears to be the odds-on favorite to take the job in Arizona.
During his time in Pittsburgh, Butler has built one of the most fearsome linebacking groups in the history of the NFL.
Known as "The Fantastic Four" by many, Lawrence Timmons, James Farrior, LaMarr Woodley and James Harrison are the prototypical example of how the 3-4 defense should look.
Though the Cardinals are known to prefer the 3-4 system, the Cardinals have often been forced to adopt the more inflexible 5-2 look, in no small part because their linebackers are the weak link.
Under Butler, the Cardinals should expect to see a much improved linebacking group, with players brought in through free agency and the draft.
A fan of the blitz, Butler's high-energy approach would be a good fit for the players the Cardinals already have.
Luke is a Featured Columnist for the Arizona Cardinals on Bleacher Reporter. He also covers the Arizona Cardinals for Sports Haze Phoenix. Follow him on twitter www.twitter.com/lukebunger and Sports Haze,www.sportshaze.com/phoenix