The decision backfired as AC Milan lost 3-1.
"Mario is not in his best period of form and has suffered from a few problems recently since that injury on international duty," said Tassotti.
"The choice was shared by the club. I don't know if Allegri spoke to the President or the general manager, but the decisions are always down to the Coach.
"The decision was made based on what we saw in previous games and training sessions. The Coach evaluated the situation and came to these conclusions."
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