The 30-year-old has yet to play in the Premier League for Karanka's side this season but he's set to be back in training before the end of the month as he continues to recover from a hernia operation in the summer.
Karanka believes the experienced midfielder's imminent return will provide a timely boost as the Teessiders have struggled so far back in the top flight.
Leadbitter has maintained his presence around the squad while being out injured but Karanka says it will be great to have him available for selection soon, with a first-team return by the middle of November a distinct possibility.
"I hope he will be training this week or next week," he said in the Gazette. "He's desperate to be back in the team. It will be a big boost, really important for the team.
"Even now when he's not in the training sessions or playing in the games, he travelled to West Ham to be in our changing room, he travelled to Everton and Sunderland because he's a really important part of this club.
"He knows that, and the other lads know too. He has a smile on his face."