The young Bulgarian could have done better for Sheffield Wednesday's goal.
The game also saw a chance for 22-year-old goalkeeper Dimitar Evtimov in the Forest sticks.
Dorus de Vries missed the game with an injury and the talented Bulgarian was therefore called in to the starting XI for the first time since joining the club from Chavdar Etropole in 2011.
The Bulgarian under-21 international put in a good performance for his first start at this level but would have felt he could have done better with the Wednesday goal.
Fernando Forestieri's strike was speculative and Evtimov should have saved it, but the ball crept underneath him to give Wednesday the lead and, eventually, the win.
"Unfortunately a young and inexperienced goalkeeper has cost us the game, but he was good before that.
"This is a priceless lesson we've learned from a young goalkeeper today."
The young keeper needed his confidence boosting, not being put down by his manager in public.
Evtimov did not deserve that and Freedman should have chose his words more wisely.