Nigerian international Ambrose was included in the starting lineup, despite having only returned from the Africa Cup of Nations in South Africa earlier that morning.
He went on to commit a handful of errors during the match, including two which resulted in goals for the Italian side.
His selection has earned manager Neil Lennon some criticism from a number of pundits, but Commons believes that Ambrose should shoulder the responsibility.
"Look, the manager picked [Ambrose]. The manager pulled him to one side and asked him if he was feeling okay. He said he was feeling brilliant," Commons said after the game.
"You know, if he wasn't feeling okay, then he should have said so. If he felt good, then he should have put in a better performance."
The return leg will be played during the first week of March in Turin.