It was a lazy, hazy Monday night at Coors Field, and between innings fans were quietly chatting and sipping sodas when a man suddenly stood from his seat and shouted, “FIRE O’DOWD!”

The man in the purple shirt, seated near the Rockies dugout, continued in a half-minute diatribe expressing his desire for the ouster of general manager Dan O’Dowd, the architect of the disaster unfolding in front of him. Later, on the Coors concourse, Brian Lenherr was spotted in a makeshift T-shirt, purple of course, with “Fire Dan O’Dowd” written on the back. On the front: “Season of a ‘century’ – 100 losses! Go Rockies!”

“It’s definitely a nightmare,” Lenherr said.

The Rockies stink but somewhat remarkably continue to draw well, ranking 13th overall in baseball attendance despite having fallen 21 games under .500.

That leaves fans who go to Coors for more than a social event — the ones who actually know the players and follow the strategy — looking for other ways to express their displeasure. Recently, two fans were spotted at Coors wearing paper bags over their heads, one of the bags reading: “YEAR OF THE FAN??” — in retrospect, a bad slogan for the Rockies to adopt this year. Local radio host Peter Burns is having T-shirts made that read “Road to 100.”

“I’m the only host in town openly campaigning for them to lose 100 games, so a change at GM is made,” Burns said. “We celebrate each loss on the show like a win.”

Fans are burning up the online message boards with displeasure; Lenherr checks out comments at the bottom of denverpost.com‘s Rockies stories “just to enjoy the cynicism.”

Other fans take to Twitter to spit their venom. At times, the Internet becomes an online support group for disaffected fans.

“But soon I realized it was like shouting at a brick wall,” explained fan Julian Mitchell, who took to shouting at the actual players from the stands. “I was at the game against the Angels and Bob Apodaca stared me down as I screamed, ‘You’re the best pitching coach in the MLB, Bob!’ Shortly after, I was pulled aside by security. I was told that if I continued to yell I would be ejected. That’s the kind of club we have where the unhappy fans are silenced if they express their frustrations. There’s nothing worse than being ignored. And I think that’s where the anger is coming from. … I’m going to a game in the couple weeks. I will be wearing a bag over my head. ‘#FireODowd’ will be written across the top.”

But fans don’t have carte blanche to vent at Coors.

“As a security measure, post-9/11, any clothing which conceals a guest’s face is prohibited, including but not limited to, costumes and masks,” explained Jay Alves, the Rockies’ vice president of communications and public relations. “That would include bags over a guest’s head.”

And the team’s policy about signs critical of the Rockies?

“Whether the club is in first place or last place, banners and signs are permitted, provided they are baseball related and in good taste,” Alves said. “Signs that contain negative messages towards our club are permitted if they do not contain offensive or profane language. … If a fan refuses to put down a sign that contains offensive or profane language, they will be asked to leave the ballpark.”

What’s a fan to do if they can’t wear a paper bag to show their disdain? Fans such as Lenherr feel almost powerless.

“The fans can say as much as they want, and the die-hards can not go, but there’s always going to be a packed stadium,” he said. “It’s just a good place to hang, and tickets are moderately affordable.”

That was never more evident than at Tuesday’s game. Official attendance on the beautiful summer evening was 42,574. Of the 14 major-league hosts Tuesday, only the Yankees, baseball’s best, outdrew the Rockies.

The losing has been tough on the Rockies’ biggest fan, or at least the fan with the most invested. At a recent private event held for fans who became season-ticket holders in the inaugural season 20 years ago, owner Dick Monfort spoke.

It was Monfort who famously told The Denver Post earlier this season, “I can’t think of a general manager in baseball that’s as good as (O’Dowd).”

On this day at Coors Field, Monfort told those in attendance, “The biggest asset of our team is our season-ticket holders. We wanted to show you our appreciation. It is the Year of the Fan. We’re trying to make this all about you. The first half (of the season) hasn’t gone anything like any of us wanted, but everyone is working extremely hard to get things going better.”

As Monfort talked, star shortstop Troy Tulowitzki suddenly showed up and took the microphone.

“He really cares about the fans. He really does,” Tulowitzki told the group. “I’ll talk to him, and the first thing he always mentions to me is how great the fans are. I wouldn’t have signed here for the amount of years that I did if I didn’t think you all were some of the best fans in the game.”

Tulo then talked about his recent injury, which initially forced him onto the disabled list and had him watching games at home on TV. “I watch every pitch on TV,” he said. “I like to play GM and try to figure out what’s going on with our team and how the quickest fix can come.”

As he said that, one person clapped, while a few others chuckled and cheered.

Benjamin Hochman: 303-954-1294, bhochman@denverpost.com