"She will run for Chancellor," Norbert Roettgen of the Christian Democratic Union said on CNN's "Amanpour
"She is absolutely determined, willing, and ready to contribute to strengthen the international liberal order. But we can't see the Chancellor or Germany as last man standing."
Germans have been waiting for months for clarity on whether Merkel will pursue a fourth term in next year's elections.
Another stint would be significant because a large part of the German electorate is looking for stability in uncertain times after the Brexit vote in Britain, the election of Donald Trump in the United States and the rise of populist movements in several European countries.
If she pursues the position, she'll be the favorite to win, political experts say, even though she is facing some backlash over Germany's refugee policies and the acceptance of hundreds of thousands of people fleeing Syria, Afghanistan and other nations.
Christian Democratic Union spokesman Jochen Blind said Merkel "will announce her decision in due time."
Holding the 'liberal order' together
On the Amanpour program, Roettgen was asked whether Merkel was willing and desirous of "holding the liberal order, in the trans-Atlantic area, together."
"The Chancellor is a cornerstone of this political concept of the West as acting as a global player. So she will run, and she will act as a responsible leader," Roettgen said.
"But it would be impossible to rely only on one person. We need the West, and the West is indispensable.
"And this of course means fundamentally and indispensably also the participation and contribution of the strongest part of the West, and this is the United States of America."
Speaking after Trump's victory last week, Merkel laid out some ground rules, of sorts, for the incoming American leader.
"Germany and the United States," she said, "are joined by common values -- democracy, freedom, respect for the law and human dignity, regardless of skin color, religion, gender, sexual orientation or political beliefs.
"Based on these values, I offer close cooperation to the future president of the United States of America, Donald Trump."
A setback in September
In Berlin two months ago, Merkel's party was knocked out of a ruling coalition with the center-left Social Democrats after winning just 17.6% of the vote.
Anti-immigrant party Alternative for Germany
entered Berlin's state parliament for the first time after winning 14.2% of the vote.
The Berlin result marked the second recent defeat for Merkel since Germany adopted its open-door refugee policy.
But nationally she is seen as a bulwark against populism and stands for an analytical, unemotional and stable style of politics.
"If I could, I would play back time so I and the German federal government and leaders could have been better prepared," she said.
First female Chancellor
Merkel, 62, is the daughter of a Protestant minister and was brought up in communist East Germany.
She entered Germany's parliament in the first post-unification election, serving in ministerial posts and as the leader of the opposition before she was finally elected Chancellor in 2005. She became the country's first female leader
She was re-elected Chancellor in 2009 and 2013.
Merkel has been a leading figure in the fight against the region's financial crisis. She has blocked bailouts, rejected proposals, denied pleas and stood up to the rest of Europe.
While citizens in France, Spain, Italy and Greece voted out her counterparts, Merkel has been re-elected with one of the strongest mandates in the history of modern Germany.