"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."
Merkel, 62, is the daughter of a Protestant minister and was brought up in communist East Germany.
Read alsoMerkel accuses Syrian government of 'crimes against humanity'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.