GETTYSBURG, Pa. — Rick Santorum announced Tuesday afternoon that he is ending his campaign for the presidency, effectively closing out the GOP primary season and cementing Mitt Romney's status as his party's presumptive nominee.

The decision to shutter his campaign comes days after Santorum's youngest daughter, Bella, was hospitalized with a chronic and serious medical condition. Santorum's team said last night that Bella had been released from the hospital and Santorum was set to resume his campaign schedule.

But in Gettysburg today, Santorum said his family had conferred over the weekend and concluded it was time to bring his White House bid to a close.

"This was a time for prayer and thought, this past weekend, just like it was, frankly, when we decided to get into this race. Karen and I and the kids sat at the kitchen table and talked about our hopes and fears and concerns," Santorum said.

Declaring that his run had enabled "conservatives to have a voice" in the nominating process, Santorum cast his campaign as the longest of long-shot enterprises.

"Miracle after miracle, this race was as improbable as any you will ever see for president," he said, insisting that while his candidacy is over, "We are not done fighting."

"I know a lot of folks are going to write, maybe even those at the White House, game over. But this game is a long, long way from over," Santorum continued.

By dropping out now, Santorum spared himself the potential embarrassment of a loss to Romney in Pennsylvania's April 24 primary. The Santorum and Romney campaigns were in communication over the weekend, sources in both campaigns said, and those talks intensified Monday.

Romney and Santorum spoke directly ahead of Santorum's withdrawal, sources said. Santorum also had a conversation with Republican National Committee Chairman Reince Priebus and planned to speak with his top supporters on a conference call later Tuesday.

Santorum did not endorse Romney in his afternoon remarks. Hogan Gidley, a spokesman for his campaign, said in an MSNBC appearance that Romney had reached out to Santorum to request a meeting about an endorsement.

In a statement on Santorum's announcement, Romney made no mention of the meeting or a possible endorsement, calling his once-bitter foe an "able and worthy competitor."

"He has proven himself to be an important voice in our party and in the nation," Romney said. "We both recognize that what is most important is putting the failures of the last three years behind us and setting America back on the path to prosperity."

Now that Santorum is finished as a candidate, Romney may now turn his attention to the general-election fight with President Barack Obama and the task of uniting a fractured Republican coalition.

That process was already under way as Santorum's campaign faltered over the past few weeks. After losing a series of big-state nominating contests — most recently Wisconsin on April 3 — Santorum had pinned his hopes for a comeback on his home state.

But Romney's campaign and super PAC have been pumping millions of dollars into TV ads there and polls have shown Santorum's lead diminishing. If Santorum had lost Pennsylvania — in addition to four other states voting that day where Romney is favored — it would have marked an embarrassing end to an impressive insurgent conservative presidential run.

Instead, Santorum now has the opportunity — if he wants to take it — to recast himself as a party leader and national conservative spokesman, perhaps reclaiming some of the prestige he lost after his mammoth 2006 reelection defeat.

(Also on POLITICO: PHOTOS: A look back at Santorum's career)

Pennsylvania GOP Chairman Rob Gleason, who spoke to Santorum earlier Tuesday, said Pennsylvania Republicans are "proud of the good work that he did as a candidate. He did a great credit to himself and our party."

And social conservative leader Gary Bauer, the former Family Research Council head who endorsed Santorum's campaign, praised his candidate for an "outstanding campaign."

"His contribution to the debate has made the GOP stronger, and will contribute to the end of the Obama administration this November," Bauer said. "He and his family have made a wonderful contribution to the future of our country."

Santorum's departure from the race leaves just Newt Gingrich and Ron Paul, the third- and fourth-placed candidates in the delegate chase, still in the contest as conservative opponents to Romney. Gingrich has acknowledged that it is all but certain Romney will be Obama's opponent in November.

Both remaining Romney opponents put out statements of their own calling Santorum's surrender a sign that conservatives ought to move in their direction.

"Dr. Paul is now the last — and real — conservative alternative to Mitt Romney," Paul's campaign said.

Gingrich, too, emphasized that he's in the race for the long run: "I am committed to staying in this race all the way to Tampa so that the conservative movement has a real choice. We know well that only a conservative can protect life, defend the Constitution, restore jobs and growth and return to a balanced budget."

This report has been updated. Reid Epstein contributed to this report.