Since the Dallas Cowboys are the lone NFL franchise without at least a nominal defensive coordinator on the coaching staff, there is certainly no confusion about who presides over the in-game decisions regarding the unit's various alignments.
Which is fine with head coach Wade Phillips, who assumed the defensive play-calling duties from then-coordinator Brian Stewart after seven games in 2008, and with owner Jerry Jones unhappy over his team's 4-3 record at the time.
"There are definitely no excuses, that's for sure," said Phillips, who has served as the defensive coordinator for six different NFL franchises during his long career. "Not that there really were before. Everybody here knows who's making the [defensive] calls, and whose responsibility that is."
Indeed, in a game replete with nickel pass-rushers and dime coverages, there is some irony that the buck stops with Phillips and others of his ilk.
There are still about three times as many head coaches who call their team's offensive plays in the NFL as there are coaches who run their own defenses. But with Phillips supplanting Stewart last year, Lovie Smith now determining schemes in Chicago, and the New York Jets' Rex Ryan personally signaling in blitzes, stunts and coverages, the subset of head coaches in the league running their own defenses is gradually expanding.
Rumors are percolating that his team's surprising 0-4 start, and a seeming inability to stop the run or the pass, might prompt Tennessee coach Jeff Fisher to take over the play-calling chores from Chuck Cecil. The first-year coordinator replaced Jim Schwartz, who departed in the spring to become the Detroit Lions' head coach.
Obviously, there are many head coaches who enjoy significant input into their weekly defensive game plans, although most of them don't take it upon themselves to serve as the club's de facto defensive coordinator. But there are occasions in which head coaches who own impressive defensive pedigrees opt to take the middleman out of the equation, and want to remove the ambiguity inherent to any sort of surrogate arrangement.
And as first-time head coach Ryan stressed almost from the moment he was hired by the Jets, there are times when a head coach simply feels more confident in taking firsthand control of a particular element of the game.
"I just feel I'm best when I'm calling my own [defenses]," allowed Ryan, who does employ a coordinator in Mike Pettine. "I've done it for so long, that it's kind of like second nature for me. And I enjoy doing it."
There are 17 head coaches in the NFL whose backgrounds and reputations were primarily earned as assistants or coordinators on the defensive side. Fourteen coaches feature mostly offensive backgrounds and one, John Harbaugh of Baltimore, was a standout special-teams coach for much of his career as an assistant. By unofficial count, about eight head coaches call their team's offensive plays. In addition to Phillips, Ryan and Smith, it's believed that Jack Del Rio of Jacksonville, a former standout linebacker in the league and a previous defensive coordinator, now calls at least some of the Jaguars' defensive schemes.
Given the current trend, and with the league skewing very slightly toward defense (eight of the past 15 head coaches hired had defensive backgrounds), the number of head coaches who call their own defensive sets is increasing.
"Guys have been calling their own offensive plays for years, no one has made much of it, and it's pretty much become an accepted thing in the league," Smith, who also employs defensive coordinator Bob Babich, told SI.com earlier this year. "I think we're going to see more of [head coaches calling their own defenses]."
That's probably the case, with head coaches choosing their own fates in a profession with a short shelf life, and despite the mixed results to date. The concept of a head coach signaling in his defenses certainly reduces the opportunities for the message to be lost in translation, but the streamlined paradigm still has an uneven success rate.
Ryan, whose extensive blitz package has added swagger to the New York defense and made the Jets one of the season's early surprises, has improved a defense that was hardly overhauled from a personnel standpoint. Entering Monday night's game, the Jets ranked No. 6 in the league in total defense, after finishing 16th in 2008. While Ryan's blitz schemes have yet to fully kick in, the Jets are performing with a palpable increase in confidence and a newfound feistiness.
"A lot of it comes straight from [Ryan]," said nose tackle Kris Jenkins. "When something works as well as this has, even the doubters believe in it, and they want to be a part of it. There's no [empty rhetoric] about it. When he says it, you believe it's going to work, and so far it has."
Even with the season-ending injury to middle linebacker Brian Urlacher, the Chicago defense seems to be improved over a year ago. The addition of longtime NFL defensive line coach Rod Marinelli, the former head coach in Detroit, has been credited for much of the Bears' progress, but Smith has also received his share of plaudits.
The jury remains in deliberation over the Dallas defense, just as it does with the overall performance of the Cowboys to this point. The Cowboys don't rush the passer well -- linebacker DeMarcus Ware, the NFL sack leader (20) in 2008, doesn't have a sack yet through four games -- and the secondary is spotty. Still, Phillip's résumé as a defensive playcaller suggests the team will get better.
In 23 games under Stewart, who took the coordinator job in 2007, the Cowboys posted a 17-6 record. In those 23 games, Dallas surrendered an average of 21.7 points, 18.5 first downs and 306.5 yards. With Phillips calling the defenses, Dallas is just 7-6, and has allowed averages of 20.6 points, 17.8 first downs and 312.8 yards. In nine games in 2008, the Cowboys permitted an average of 21.1 points, after allowing 25.0 points in seven games under Stewart's direction.
Len Pasquarelli, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com.