HIALEAH, Fla. — Marco Rubio’s homecoming to Florida will likely be far from the triumphant one many Republicans once expected and that his campaign had banked upon.

Instead, the pivotal state could well be Rubio’s last stand in his party’s presidential primary. When the Republican field meets to debate Thursday in the tony enclave of Coral Gables, the Florida senator will trail Donald Trump by roughly 17 points in the RealClearPolitics polling average, still reeling from a punishing round of primaries Tuesday in which he won no delegates.

During an interview with CNN on Wednesday, Trump promised a “nicer, softer, lighter” debate, in contrast to the recent raucous gatherings. But his rivals are making no such assurances.

Rubio now characterizes himself on the campaign trail as an “underdog,” but his standing is more precarious than that label would suggest. The freshman lawmaker faces new, acute pressure from some Republicans to drop out of the race so that the party might unite behind an alternative to Trump; meanwhile, Rubio’s campaign has spent much of this week batting down rumors that he would indeed end his bid for president.

At a rally here Wednesday, the candidate rejected the idea that he would drop out prior to the Florida primary. “Let me tell you something: I will be on that ballot Tuesday,” Rubio promised. “I’m going to campaign as long and as hard as it takes.” If his supporters heard any rumors that he would drop out, Rubio warned them not to pay the gossip any mind.

But the event itself seemed to confirm his shaky predicament. Staged on what should have been friendly turf, in a city where two-thirds of the population is of Cuban descent, and in proximity to Rubio’s hometown of Miami, only a meager crowd showed up to cheer their senator. Amplifying the disappointing showing was the venue: a football field and stands, empty but for a cluster of supporters and Rubio’s stage in one end zone.

The candidate acknowledged the small turnout as he walked onstage, immediately explaining that the “town of working-class people” was “just getting out of work.”

The rally might have been one result of Rubio’s late focus on Florida as he has waged a more national campaign for the presidency, so far with discouraging results. His campaign only began opening offices in the Sunshine State within the past few weeks, including his Miami headquarters. Meanwhile, the financial strain of the early primaries appears to be taking its toll: Rubio will not air any television ads in Florida this week, the Wall Street Journal reported Wednesday.

Now, the Republican debate Thursday might be his last best chance to stop his campaign’s apparent collapse.

“He needs to have a heck of a debate Thursday to be able to accomplish it,” Al Cardenas, a former Rubio ally who endorsed Jeb Bush, told Bloomberg News on Tuesday. But when asked whether he thinks Rubio has “zero percent chance of being the nominee,” Cardenas responded: “At this point, yes.”

Rubio distinguished himself during the most recent debate, in Houston last week, for inspiring an awkward discussion about the size of Trump’s hands — one in a recent barrage of taunts Rubio had directed toward Trump on the campaign trail, including jokes about his “orange” tan and his hair.

At a town-hall event Wednesday, when asked if those comments were in keeping with his Christian faith, Rubio admitted his attacks were “not something I'm entirely proud of.”

"My kids were embarrassed by it,” he said, “and if I had to do it again, I wouldn't." (He did, however, defend his attacks on Trump's business record.)

It appears the assault on Trump did not serve him well, either. Rubio’s performance Tuesday showed a sharp decline in his share of the vote, and his allies predicted it would not bode well for his survival in Florida and in the race.

“It’s devastating,” said one senior Republican operative who backs Rubio. “There’s no way around it.”

Trump and Ted Cruz immediately attempted to take advantage of Rubio’s stumble, a trend that will likely carry over into the debate Thursday. "I think it's time now that he drop out of the race," the front-runner said of Rubio on Tuesday. Cruz, appearing at a rally in Miami on Wednesday morning, played up his own Cuban roots to a crowd of Rubio’s constituents.

Meanwhile, some of the Republican Party’s stalwarts are staying on the sidelines. Although Mitt Romney drew headlines last week for his attacks on Trump, Romney has not made known his preference among Rubio, Cruz and Ohio Gov. John Kasich. Those three candidates will each meet this week with Jeb Bush in Miami, but it is unclear whether the state’s former governor plans to endorse any of them.

To the winner of Florida will go considerable spoils: The primary Tuesday will be among the first winner-take-all contests of the election cycle, with a whopping 99 delegates at stake. It could be enough to set Trump on an irreversible path to the nomination, although many Republicans are holding out hope that that will not be the case.

Florida is not the only big prize up for grabs next week: Kasich will attempt to fend off Trump in his home state of Ohio, another winner-take-all contest. Polling suggests he is well-positioned to best Trump, although his strength will no doubt make him a target in the debate and of his opponents’ television advertising.

But if the game is on in Ohio, it seems to be on the wane in Florida. At Rubio’s rally Wednesday, one speaker invoked Yogi Berra: “This game’s not over ’til it’s over.”

In less than one week, the subtext seemed to read, it might well be for at least one of the remaining four GOP candidates.