BERLIN—Germany signaled it is prepared to reconsider its Nord Stream 2 gas pipeline project with Russia in light of the poisoning of Russian opposition figure Alexei Navalny, who was roused from an induced coma on Monday.

Chancellor Angela Merkel, who has been a champion of the pipeline project, couldn’t rule out including Nord Stream 2 in possible sanctions against Russia should Moscow fail to investigate Mr. Navalny’s poisoning, a spokesman for the German leader said.

Germany’s reaction would depend on Russia’s actions in the coming days, the spokesman said.

Berlin’s Charité hospital said Monday that Mr. Navalny had been awakened from a coma and was responsive. German scientists determined last week that the opposition figure had been poisoned with Novichok, a Soviet-era military-grade nerve agent.

Mr. Navalny, who was flown to Berlin for treatment with the help of the German government on Aug. 22, could still suffer long-term damage, the hospital said. He is now being weaned off mechanical ventilation as his condition improves, according to the clinic.