The 20-year-old has been sidelined for much of the season with a knee ligament injury but after he extended his stay at the Riverside Stadium until 2015, Main has admitted that he is eager to begin playing again.
Main told the club's official website: "I'm grateful the manager has shown faith in me.
"I can't wait to restart full training and get playing again.
"I've really enjoyed my time here and I hope I can continue to make progress. I realise there is stiff competition for places, but that will only spur me on."
Main has scored two goals in 14 league appearances for Middlesbrough.