One security guard, who did not want to give his name, said employees knew Caesars was expected to close one of its four Atlantic City casinos, but they were thinking it might be Bally's.
"We never thought it would be us," he said.
News of Showboat's possible closing comes six months after another Boardwalk casino, the Atlantic Club, closed, and a week after the $2.4 billion Revel announced it was in bankruptcy for the second time. Revel's owners said that it, too, would close if a buyer is not found by Aug. 18.
Caesars chief executive Gary Loveman may have forecast the Showboat closure in a call with investors last month.
On a May 7 quarterly earnings call, Loveman predicted that some of the gambling halls in Atlantic City would have to close.
"There is too much capacity in Atlantic City currently, such that the returns to existing capacity are under great pressure," Loveman said. "So we're looking at all of our options to continue to reduce the cost of doing business here, options to reduce capacity."
John Heinz of Galloway, a former employee who was at Showboat as a customer Thursday night, wasn't surprised to hear of another blow to Atlantic City's gambling industry.
"It seems like it's been going on for a long time," he said. "I'm not sure we've quite hit the bottom. It's going to take a lot of cohesive planning to figure out the next chapter."
The severe downturn in Atlantic City started about eight years ago, when Pennsylvania opened the first of a dozen casinos. Since then, it has been a precipitous decline for Atlantic City's gambling revenues. New York, Maryland, and other surrounding states have since opened or added casinos.
Atlantic City has shed about 40 percent of its total gaming revenue since 2006 - going from a peak of $5.2 billion to just under $2.9 billion last year.
Caesars' four Atlantic City properties saw a 14 percent drop in net revenue this winter vs. last, which Loveman blamed not just on all the snow, but also on the growing competition from betting halls in Pennsylvania - including Harrah's Philadelphia in Chester, owned by Caesars - and elsewhere in the Northeast.
Showboat is also in a troubled Boardwalk spot, sandwiched by Trump Taj Mahal and Revel.
"When the Revel joined the market, as you all know, it didn't do anything to grow it, instead it just took a portion of the existing level of activity," Loveman said in May.
Calls to Caesars' corporate office were not returned Thursday. Staff reached by phone at the Showboat said they had not heard of the closure and were not authorized to speak about it.
McDevitt said the union immediately began notifying its Showboat members of what they would see Friday - letters in accordance with the WARN Act, giving employees at least 60 days' notice of a planned business closure.
Assemblyman Christopher A. Brown (R., Atlantic), who sits on the Tourism, Gaming and the Arts Committee, said his heart goes out to the 2,000-plus families that would be affected by Showboat's closing.
"This is painful news," Brown said late Thursday. "We are not talking about credits or debits on a spreadsheet. We are talking about human beings who get up every day and work hard to provide for their families. We owe them our best and continued efforts to turn Atlantic City around."
Showboat Atlantic City is a Mardi Gras-themed casino with a 1,300-room hotel and a House of Blues restaurant and concert venue. The casino opened in 1987, and in 2003 it added the 544-room, $90 million Orleans Tower.
In terms of net revenue, Showboat is the smallest of Caesars' Atlantic City properties. But in the first quarter of this year, Showboat had an operating profit of nearly $2 million, while Bally's had a loss of $1.6 million.
Showboat had an operating profit of $34 million on net revenue of $197 million in 2013, compared with Bally's operating profit of $33.5 million on net revenue of $302 million.
Revel, which employs about 3,500 people and has been open only 27 months, is set for auction Aug. 6.
McDevitt said last week that the best thing for Atlantic City would be for Revel to find a buyer and remain in operation to maintain jobs for its employees.
In mid-January, the tiny Atlantic Club on the southern end of the Boardwalk shut its doors for good when it could no longer sustain its revenue losses and compete with the bigger gambling houses both in town and out of state. About 1,700 employees lost their jobs in that closing.
At Showboat, business trudged along Thursday night - guests checked in, visitors left their cars with the valet, gamblers headed to the video-poker machines.
A bartender who said he had been there since Day One called the expected closure "very dispiriting." Losing his job would send him out of Atlantic City the same way he arrived nearly three decades ago.
"I came looking, and I'll have to leave looking," he said.
Inquirer staff writers Harold Brubaker and Joseph N. DiStefano contributed to this article.