MELBOURNE, AUSTRALIA - JANUARY 11: Joel Smith of the Demons in action during the Melbourne Demons training session at Gosch's Paddock on January 11, 2017 in Melbourne, Australia. (Photo by Adam Trafford/AFL Media/Getty Images)

Melbourne defender Joel Smith will make his AFL debut against St Kilda on Saturday after being elevated to the senior list on Thursday.

The 21-year-old was promoted after ruckman Mitch King was placed on the long-term injury list.

“It’s a bit of a shock and I didn’t expect it,” Smith told Melbourne TV.

“A year ago, I was playing in the VFL Development [League] and here I am now playing round one against St Kilda and I’m rapt.

“All of the hard work has paid off and I just can’t wait to be out there.

“As pre-season went on, I was training really well and I thought I could actually do this.

“I played a couple of JLT [Community Series] matches and the last few weeks I’ve been thinking about it and it’s been in the back of my mind.

“Now I’m playing, I’m ready to go and I can’t wait.”