AC Milan director Umberto Gandini has been forced to apologise tonight for making an administrative error which saw M'Baye Niang left out of the club's squad for the Champions League group stages.

Niang was a surprise omission from the 25-man squad Milan submitted to UEFA this evening, with Gandini taking full responsibility for leaving the young Frenchman out by mistake.

Milan included Stephan El Shaarawy on an A list of players, even though aged 20 with two years service at the San Siro he could have been on the B list reserved for academy graduates.

That mistake meant there was no room for Niang on the A list, an oversight for which Gandini admitted that he was culpable in a brief statement on Milan's official website tonight.

It read: "Umberto Gandini, Director of AC Milan organization, has assumed the responsibility for the error in the completion of the lists Champions League.

"Gandini regrets this error and apologises to all parties concerned and professionally to the Rossoneri fans."

Summer signings Andrea Poli and Kaka were included, ahead of the Rossoneri's challenge in Group H against Barcelona, Ajax and Celtic.