Goals from Daniele Baselli and Afriyie Acquah arguably should have been enough for the hosts to move up to ninth with the victory, only for the on-loan keeper to concede a pair he would love to have back.
With the game scoreless in the 27th minute, Hart only got a touch on Geoffrey Kondogbia's low drive and watched as it slowly trickled into the net to give Inter the lead.
After Baselli's equalizer six minutes later, Torino would go up in the 59th minute thanks to Acquah. But while Hart perhaps could be forgiven for not being quick or strong enough on Inter's opener, there aren't any good excuses for the second.
Hart just missed a cross into his six-yard box, appearing to misjudge the flight and over-run it as he came for the ball. The chance fell to Antonio Candreva, who buried the shot into the empty net to level the score in the 62nd minute. That's how it finished.
Manchester City keeper Omar Bravo has been befallen by numerous gaffes on his own this season, leaving City fans wondering if the club would have been better off keeping Hart instead.
But on this night, the English keeper did not make a compelling argument as to why he should again be City's No.1, if he returns to the club when his loan finishes.