But whatever the dynamics, the stakes are usually as high as the emotions.
"It's a very big decision for a coach to have to make. Probably one of the biggest," Dick Vermeil, the former Eagles, Rams, and Chiefs coach, said from his California winery. "But I think many times the decision gets distorted because it's the quarterback position."
Past controversies have killed the careers of veteran QBs, destroyed the confidence of young ones, turned teammate against teammate, soured fans, and, as could easily be the case in Philadelphia, where a conventional dispute involving then-starter Kevin Kolb and backup Michael Vick turned nuclear this week when Andy Reid flip-flopped them, jeopardized the jobs of the coaches who created them.
"I've never really been involved in one," Vermeil said. "But I've followed and evaluated them, and they can be very distracting. They can be team-dividing."
Quarterback decisions are among the most difficult and risky NFL coaches face. A few years ago, Arizona's Ken Whisenhunt created a furor but got to a Super Bowl by benching No.1 pick Matt Leinart in favor of veteran Kurt Warner.
While many factors are at play in the origins of a QB controversy - motivation, competition, a desired change of pace - there's no doubt self-preservation often plays a big role.
With Whisenhunt, "People were saying, 'What are you doing? Matt Leinart is a top 10 pick. Play the young guy and get him experience with those great wide receivers,'" said Tim Hasselbeck, a former Eagle, Redskin, Giant, and Chief and now an ESPN analyst. "But Whiz looked at it like this: 'If I win two games this year and four games next, my job will be on the line. I need to win now. And even though Warner had put bad years together in New York and his last season in St. Louis, he gives us the best chance and I'm going to play him. It's maybe not the best long-term solution, but it's what I'm going to do.'"
Rich Gannon, the Philadelphian who got caught up in several quarterback controversies during a long career as an NFL quarterback, identified another risk. When a coach demotes a starting quarterback, particularly a popular one, a pall often descends over his team.
"It becomes really awkward," said Gannon, now a CBS analyst. "You see them in the locker room and you don't know what to say. It's almost as if a friend has died. What do you say, 'Sorry'?"
Gannon continued, "It's not an easy thing to go through for the player or the team. Guys like Jeremy Maclin and DeSean Jackson have developed a great rapport with Kevin Kolb. They've taken all the reps. They've talked to him about all the adjustments and things. Now all of a sudden, in one short week, they're not dealing with Kevin anymore. It's awkward."
Real problems erupt when, as happened with Troy Aikman and Steve Walsh on Jimmy Johnson's first Cowboys team and earlier in San Francisco with Joe Montana and Steve Young, one quarterback feuds with another.
"It's really important to have a healthy quarterback meeting room," Gannon noted. "You want guys that challenge each other but get along. You don't want tension or friction."
Typically, as with Warner-Leinart and Vick-Kolb, the dramatic theme is youth vs. experience. But there's no playbook on the subject and often the coach's choice is between differences in styles, contractual status, even locker-room standing.
A coach might switch quarterbacks to send a message to his starter, or to quiet his owner, players, or fans, or when he admits to himself that his previous decision was the wrong one.
Sometimes, especially when a franchise quarterback emerges, a coach gets lucky. More often than not, until it resolves itself, he's left with turmoil in the locker room, in the stands, even on the field.
The only surefire way to avoid trouble is to uncover a long-term solution, either through the draft, free-agency, a trade, or the painstaking process of competition. And even that might not be enough to pacify fickle fans.
"The fans' favorite player is always the backup quarterback," said Charlie Casserly, the former Redskins general manager and now CBS analyst who survived the contentious Jay Schroeder-Doug Williams dispute in Washington. "Clearly, you're not going to have a controversy in Indianapolis or New England or Green Bay. But everywhere else they're inevitable, and when they happen the best you can hope to do is manage it."
In trying to do that, coaches have attempted all sorts of solutions, mostly without success. On the great L.A. Rams teams of the early 1950s, Bob Waterfield and Norm Van Brocklin alternated quarters. When Dallas' Tom Landry couldn't decide between Craig Morton and Roger Staubach in the 1970s, he shuttled them in and out on every play, much as he'd done with Eddie LeBaron and Don Meredith on his first Cowboys team.
In those instances, and in perhaps the most famous quarterback controversy, the one involving the Niners' Montana and Young, the debate was ultimately settled with a trade.
If 77 years of NFL history has provided any lesson on the subject, it's that if you don't have a future Hall of Famer at the position - or, as with Montana and Young, you have two - there's no simple way to choose your quarterbacks or to rank them on the depth chart.
Teams caught up in controversy often act rashly, as when the Redskins platooned Hall of Famer Baugh and Frankie Filchock in 1944, or when New England gave Drew Bledsoe a 10-year, $105 million extension even though it had Brady in the wings.
Vermeil, who made Warner his starter in St. Louis only after Trent Green was hurt, suggested the ideal way to handle quarterbacks was to find a young talent and mentor him with a veteran backup who also serves as an insurance policy.
"The backup has to be able to go into a ballgame and play well without many repetitions in practice," said Vermeil. "Normally, young kids can't do that. Normally a veteran can. Young guys can struggle even when they're getting all the reps. They'd have a really hard time coming in in the third quarter after getting maybe 10 reps all week."
Gannon, who played 14 years before leading Oakland to Super Bowl XXXVII, got caught up in controversies in Minnesota (with Wade Wilson and Sean Salisbury) and Kansas City (with Elvis Grbac). The inevitable result, he said, was failure.
"I've never been on a team where there have been two guys in this kind of situation that's made it deep into January," he said. "Look at most of the teams that have made changes already - Buffalo, Cleveland, Carolina, Oakland. Those teams for the most part aren't going to be playoff teams.
"Andy's going to make a decision in the best interest of the team. That's why it surprised people when he said, 'This is our guy', then changed his mind a week and a half later. I'd be the last guy to second-guess Andy Reid, but that was strange."
Because there aren't enough Bradys, Peyton Mannings, and Drew Breeses to go around, and because the NFL is so intensely focused on quarterbacks, at some point doubts are going to emerge about all the others.
When that happens, and the fans are lighting up the talk-radio switchboards, the onus falls on coaches like Reid. The right move can guarantee him even longer-term stability. A mistake could soon have him looking for work.
That knowledge alone can alter the dynamics of a controversy. Last week, for example, in the midst of the Raiders' victory over the St. Louis Rams, Oakland's Jason Campbell, whose team was trailing by only 7-3 and who seemingly was playing well, was replaced by backup Bruce Gradkowski.
"I watched that game twice and I still can't figure out why Jason Campbell got benched," Hasselbeck said. "But [Raiders owner] Al Davis, I think, believes in Campbell and I don't think coach Tom Cable does. So Cable is going to play Bruce whenever possible because he believes he has the best chance of winning enough games to save his job."
Certainly, Reid's status doesn't seem that precarious. And even if it were, in Vermeil's opinion at least, it probably wasn't a factor in his decision to reverse field and start Vick against Jacksonville.
"I'm sure Andy Reid will handle this successfully, and I'd be willing to bet it's being successfully handled in that organization right now," Vermeil said. "I think coaches instinctively and intuitively just do what they think gives them the best chance to win, because they have the responsibility to their roster, to ownership, and to the entire community.
"Most coaches I've known well have no concern about the security of their jobs. They're just interested in doing a good job."
Vermeil recalled when he was a young head coach at UCLA in the early 1970s. He had three running backs with ability and was unsure how to juggle them. So he sought advice from a wizard.
"In the office right next to mine was John Wooden," he said, referring to the legendary UCLA basketball coach. "I was sitting there and I told him, 'I've got three pretty darn good running backs and it's hard to keep them happy.' You know what he said to me? He said, 'Don't worry about keeping them all happy. Just make sure you keep the best one happy.' "
Contact staff writer Frank Fitzpatrick at 215-854-5068 or at firstname.lastname@example.org.