Nigeria coach Berti Vogts has ordered his squad to report early for a pre-tournament training camp, and under FIFA rules, there is nothing Allardyce can do to stop it.
Martins Heads Away In January!
Allardyce had hoped to persuade Vogts to relax his hard-line stance.
But with Vogts under intense pressure to guide the Super Eagles to their first ANC title since 1994, he has not relented, and Martins will miss six United games should Nigeria go all the way in the tournament, which is being held in Ghana.
Allardyce: "We've got no muscles to flex.
"It's a FIFA rule - there's a two-week period prior to an international tournament starting that for which they can take the players. If he's not within his rights to do it, then he wouldn't be doing it.
"At the moment (Vogts) is the only one who is invoking the rule."