Leaving the country would allow him to be tried in absentia thereby avoiding any jail time if convicted.
In Germany, a new nationalist party came third in last year's elections, putting pressure on Merkel by limiting her options for a new government. "He's a terrorist agent", Erdogan said at the time. "I am of the opinion that there will be a development soon", Yildirim said in a translation provided by state-run broadcaster ARD.
"I do not know why I was released today", said Yucel in the video. The Turkish government responded by accusing Germany of using "Nazi methods".
However, she also called Yildirim's visit "a signal that both sides have the will to improve German-Turkish relations. even if that's not so easy at the moment".More news: Wales shaken by 4.4 magnitude natural disaster
German Chancellor Angela Merkel welcomed his release Friday, saying she was happy for Yucel and his family "who had to endure a very hard year of separation".
Ties between Ankara and Berlin have been strained over a number of issues, including restrictions on Turkish government officials holding rallies in German cities a year ago and the detention of German citizens in Turkey.
On Friday, Yildirim cautiously welcomed Yucel's release, suggesting it would ease tensions with Berlin. "These meetings with people from Turkey are events that should not trouble Germany", he said.
Yucel gave himself up to police previous year after initially taking refuge inside a German diplomatic compound in Istanbul following reports that a warrant had been issued for his arrest. The high-profile case and that of six other German citizens held in Turkey for what Berlin considers political reasons have soured relations between the two countries.More news: Chabahar will be a golden gateway, says Narendra Modi
Berlin had past year advised German investors and holidaymakers to avoid Turkey.
German Chancellor Angela Merkel said she was "delighted for him, for his wife and family", thanking all those who had worked for Yucel's release.
The spokeswoman said that Berlin had not agreed to any "dirty deals or other arrangements" to secure the release.More news: Apple employees are walking into the 'spaceship campus' glass walls