Bonera starts for Milan, Villa on Atletico bench
AC Milan's Dutch coach Clarence Seedorf smiles during a training session on the eve of the Champions League match between AC Milan and Atletico Madrid, on February 18, 2014 at their Milanello training center in Carnago - by Giuseppe Cacace
Mexes had recently returned to Seedorf's starting line-up but after a mediocre performance against Napoli was also left out of the win at home to Bologna last week.
Former Milan great Seedorf, in his first Champions League game as coach, starts with his preferred 4-2-3-1 formation with Nigel De Jong and Michael Essien adding the muscle in midfield.
Recent recruit Adel Taarabt keeps his spot on the left wing, with Kaka through the middle and Andrea Poli on the right supporting Mario Balotelli in the attack.
Atletico start in their classic 4-4-2 formation that has helped put them in Spanish title contention.
Coach Diego Simeone left striker David Villa on the bench with Raul Garcia helping spearhead the attack with Diego Costa, who has scored 21 goals in the Spanish top flight this season.
AC Milan (4-2-3-1)
Christian Abbiati; Mattia De Sciglio, Daniele Bonera, Adil Rami, Urby Emanuelson; Michael Essien, Nigel de Jong; Andrea Poli, Kaka, Adel Taarabt; Mario Balotelli
Atletico Madrid (4-4-2)
Thibaut Courtois; Juanfran, Miranda, Diego Godin, Emiliano Insua; Arda Turan, Mario Suarez, Gabi, Koke; Raul Garcia, Diego Costa
Referee: Pedro Proenca (POR)