As the kickoff approaches, there is concern about the looming possibility of the University of Hawaii football team playing before the smallest season-opening gathering in its Aloha Stadium history.

The Sept. 3 start against Colorado is less than three weeks away now and barring a surge in individual and walk-up sales or a ticket giveaway, the Rainbow Warriors could debut to a half-full stadium for the first season opener since moving there in 1975.

UH officials have been reluctant “to throw out an (attendance) number” for the opener but concede that amid current trends anything above 25,000 through the turnstiles at the 50,000-seat facility might be cause for rejoicing.

In 32 previous season openers in Halawa the smallest gathering through the turnstiles was 26,532 for the kickoff of the 1977 campaign against New Mexico.

Not since that game, which marked Dick Tomey’s debut as head coach, have the ’Bows attracted fewer than 28,173 to begin a season.

But, then, never before have they had the confluence of factors that surround this opener, either. The game will come not on a traditional Saturday but at 7 p.m. on a Thursday night preceding the final work day before the Labor Day weekend.

After a proposed UH-CU matchup in Australia fell through, the game was shifted off the contracted Sept. 5 date to accommodate Colorado’s request for a little breathing room on its schedule.

The Buffaloes are one of only two teams in the 129-member NCAA Football Bowl Subdivision embarking upon a 13 games-in-13 weeks scheduling grind this season. The other is, of course, UH.

Subsequently, under terms of the Mountain West television contract, the game was snapped up by the CBS Sports Network, from which UH derives no fees for the televising of the game. The network is widely available on cable systems here, giving potential game-goers an easy, stay-at-home option.

Colorado is the only opponent from a Power Five conference on UH’s home schedule, one that lacks ranked teams, and that has impacted season-ticket sales, which are running at their lowest point in more than 35 years.

Despite a so-far-promising beginning to training camp, the shadow of four consecutive losing years hovers over season-ticket sales. As of Friday, UH said 18,874 tickets had been distributed, taking in season tickets, individual sales, corporate partners, etc.

Season-ticket sales had been running about 14,500 and UH said it expects to reach the 15,000 mark by the season opener, but that would still be well short of the 2014 total, 17,224, which was the previous low.

Meanwhile, Rainbow Wahine season-ticket sales (3,631) are expected to match last year’s total of 3,861, one of the highest in recent years.

Individual football game tickets went on sale this week and UH officials are hoping that a continued positive vibe from training camp combined with the emergence of quarterback Max Wittek will spur individual and game-week walk-up demand.

So far, it is a wait-and-see customer base with the emphasis on the “wait.”

Reach Ferd Lewis at flewis@staradvertiser.com or 529-4820.