He is expected to be one of four United players involved in the tournament, which takes place in Ghana in January and February.
Manager Berti Vogts has also insisted all 31 members of his squad report for a pre-tournament training camp in Spain from January 4.
Should the Super Eagles reach a seventh final of the biennial competition, Martins will miss the games against Stoke City, Manchester United, Bolton Wanderers, Arsenal, Middlesbrough and Aston Villa.
Martins is one of eight British-based players in Nigeria's squad, though there is no place for Everton's Victor Anichebe.
His clubmates Joseph Yobo and Ayegbeni Yakubu were named alongside Nwankwo Kanu, John Utaka (both Portsmouth), John Obi Mikel (Chelsea), Dickson Etuhu (Sunderland) and Seyi Olofinjana (Wolves).
His clubmates Joseph Yobo and Ayegbeni Yakubu were named alongside Nwankwo Kanu, John Utaka (both Portsmouth), John Obi Mikel (Chelsea), Dickson Etuhu (Sunderland) and Seyi Olofinjana (Wolves).
Didier Drogba, Salomon Kalou (both Chelsea), Kolo Toure, Emmanuel Eboue (both Arsenal), Abdoulaye Meite (Bolton), Emerse Fae (Reading) and Didier Zokora (Tottenham) are in the Ivory Coast's provisional squad.