HAWTHORN star Tom Mitchell is on the mend after undergoing surgery to repair the broken leg that put a line through his 2019 season before it had even begun.

Mitchell posted a series of photos on his Instagram account, with the main picture showing him in a hospital bed following the operation that was needed to repair the broken tibia and fibula bones in his left leg.

The reigning Brownlow medallist expressed his gratitude for the support he had received after sustaining the season-ending leg injury at training on Friday.

"I am overwhelmed by the amount of visitors and kind messages I have received. I am grateful for all of the support I have around me. My partner, my family and friends, my teammates, the medical team, the football club and our supporters," Mitchell wrote.

"The highs and lows can change in a second but I am up for another challenge and will be back out there in no time."

One of the photos in the post contains an image of Mitchell lying on the ground surrounded by Hawthorn training staff and an ambulance crew.

An ambulance was called to Waverley Park after Mitchell suffered the injury.

Returning in the first session following the Christmas break, the ball magnet sustained the injury during a tackling drill.

The Hawks are confident Mitchell will make a full recovery but it is almost certain that he'll miss the entire 2019 season.