The Opposition Democratic Bloc agreed on Mouaffaq Nyrabia to bid planned Coalition elections next July to succeed Ahmad Jarba , source said.
Nyrabia, who represents the faction of veteran secular dissident Michel Kilo, is a former political prisoner and currently the NC representative in the European Union.
Other opposition blocs as Muslim Brotherhood have agreed on Riad Hijab, the former Syrian Prime Minister who defected in 2012, to rival Nyrabia.
In July 2013, the Coalition elected Jarba as its president on following a close run-off with businessman Mustafa Al-Sabbagh.
Activists said Jarba had enjoyed presidency merits even he behaved in some occasions as a tyrant. Such practices have negatively reflected in the ground battles, they said.
Syria's three-year conflict began as popular protests against four decades of Assad family rule but changed into armed insurgency under a security force crackdown.
More than 162,000 people killed and over 9 million forced to flee their homes.