Doug Marrone had a reputation for being thin-skinned during his time at Syracuse. That hardly makes him unique in the coaching fraternity. Marrone laughed it off on the day he was hired to coach the Bills.

But it took Marrone just three days to lose his cool in training camp. Mario Williams had missed the first three practices with a mysterious foot injury. Marrone had no answers. He didn’t even know which foot it was.

When reporters pressed Marrone for details last Tuesday, he assumed an aggrieved, defensive posture. Marrone said he was frustrated with the line of questioning. He said he was waiting to hear from the doctors.

The AP’s John Wawrow persisted. He asked Marrone if Williams, who had left camp to seek a second opinion, had been excused from camp by the team.

“That’s not a legitimate question,” Marrone snapped.

Sorry, Coach, but when we’re talking about the highest-paid defensive player in NFL history, a franchise player with a history of nagging injuries and bizarre off-field drama, there are no illegitimate questions. Everything is fair game.

It was astonishing to think that an NFL head coach would be in the dark about a star player – or any player, really – two days after the guy had missed the opening of training camp with a curious injury.

Marrone thought the media was “coming at him” in Pittsford? Seriously? They would have been coming at him like vultures in New York or Philadelphia, where the media are much less willing to take “duh” for an answer.

Legitimate questions?

We’re not talking about some undrafted free agent here. Not so long ago, remember, Williams was answering questions about a $785,000 engagement ring and whether he had contemplated suicide or abused painkillers.

It’s always something with Williams. Last week, a Houston TV station reported that Williams received special treatment from Lone Star State College, where he received a law enforcement degree earlier this year. The academy has been suspended while state regulators investigate.

The Texas Commission on Law Enforcement received a complaint about a cadet who did not meet the usual standards for completing a peace officer course, according to the TV report. The name of the cadet involved is blacked out in the report, but it’s Mario.

Then there was the flap in minicamp, when Williams said defensive coordinator Mike Pettine always told his defensive players to “kill ’em or hurt ’em.” Mario walked it back the next day, saying Pettine “never” said such things. Really, was he oblivious to Gregg Williams and the bounty scandal?

Oh, and the gun thing. Williams posted a photo on his Instagram page making fun of Aaron Hernandez after the former Patriot was accused of murder.

He depicts Hernandez as a character from “Grand Theft Auto New England.” Williams has also posted photos of himself holding automatic weapons.

As Tim Graham pointed out, Williams is well within his rights to own guns and be proud of them. But in the current NFL climate, where league officials and former players are urging players not to own weapons, it’s weak and childish behavior from one of the NFL’s most prominent athletes.

Have I left anything out? I feel sorry for Marrone, in a way. He’s a first-time NFL head coach. Toto, we’re not in Syracuse any more. Marrone better to get used to answering questions about Mario.

He’ll get grilled every time his defense gets shredded and Williams has an average game. He’ll be asked about the foot, of course. Mario has marked his foot in the dirt, providing him a convenient excuse when he plays below expectations – same as he did with the wrist a year ago.

Marrone isn’t stupid. He has to see the latest Williams injury in a larger context. A year ago at this time, Mario had a bad wrist. He said it was a big deal. Chan Gailey called it one of those “little things.” The Bills didn’t even list it on the injury report early in the year. The NFL wound up fining them for withholding injury information.

It was an embarrassment to the Bills organization. It made Gailey appear weak and out of touch. Ultimately, losing did Chan in. But the Williams injury added to the sense that Gailey was out of his depth as the leader of an entire NFL operation.

Marrone looked that way last Tuesday, like a man without total grasp of an important situation.

I’m sure Gailey is amused. But the common denominator is the $100 million man. This makes two years in a row that Williams has made his head coach look clueless about his health.

A day after his media dustup, Marrone was conciliatory. He could have handled things better, but coaches don’t like it when they lose command of a situation. No doubt, he would rather have the attention focused on his team’s progress in training camp.

I’m sure the Williams talk gets tiresome. It’s a new era, after all, with a new, exciting quarterback in EJ Manuel, and all those speedy receivers. I’m intrigued, too. I can’t wait to see them in the opening exhibition a week from today, against players who aren’t wearing the same jerseys.

But you can’t dismiss Williams as yesterday’s news. When you make a guy the highest-paid defensive player in history, the story doesn’t go away. You can’t pretend he’s just another player, a passenger in the rosy transition.

The Bills paid for a superstar and got a drama king. Williams came here with a reputation for little injuries. He’s done nothing to change that. Two training camps, two injuries that required a second opinion. Again Saturday, he did not take part in team work.

I’ll stick with my initial opinion: He’s physically and emotionally fragile.

That doesn’t mean Williams can’t have a decent year and get double-digit sacks again. He might even have a big game against a team with an elite offense. But I could see another uneven season that has people asking, again, if he was worth that staggering investment.

Amazing as it sounds, people are already wondering if Williams will ever see the end of his six-year deal. If the Bills lose and the embarrassments keep piling up, they could decide to cut their losses and move on, as they did with Ryan Fitzpatrick.

It is, at the very least, a legitimate question.