But he took that to an even higher level after he played a significant role in the Swans' 44-point victory over Essendon after being substituted into the game just 10 minutes into the second quarter.
Substitutes typically have to curtail their nervous energy until around three quarter-time, but a hamstring injury to Tommy Walsh early in the second quarter forced Mitchell to lose the green vest and enter the fray.
By game's end, he would tally 18 possessions, six marks, six tackles and a goal, one day after his 20th birthday.
"Rob Spurrs our conditioning coach just told me to keep warming up as you could be thrown into it at any stage of the game," Mitchell said after the Swans' 17.13 (115) to 10.11 (71) victory.
"When Tommy Walsh unfortunately went down, I had to get on the ground a little earlier than I probably expected.
"I just wanted to get out there and play my role and contribute.
"I just followed the direction from the senior players who were great the whole game just positioning me where they wanted me to be.
"I'm not sure if it's really soaked in yet, but I'm really happy to be part of a great win against a quality side like Essendon."
The son of Swans' Hall of Fame member Barry Mitchell, Tom had overcome some ongoing knee tendonitis to play the past seven weeks in the reserves, dominating the NEAFL over the past month.
His head coach John Longmire felt the wet, grinding conditions were tailor-made for the youngster.
"We lost Tommy Walsh pretty early, which forced Tommy Mitchell to come into the game," Longmire said.
"He looked more than at home at times.
"You saw what he's about tonight. He's very hard, he tackles ferociously and he's a good decision-maker under pressure.
"He ended up doing quite well tonight for his first game and didn't look too far out of it."
James Dampney is a reporter for AFL.com.au. Follow him on Twitter: @AFL_JD
