BIG-BODIED Collingwood midfielder Brayden Sier will debut in Saturday night's clash with Gold Coast at Metricon Stadium.

The Pies will be without Adam Treloar, who has injured both hamstrings, and have chosen the No.32 selection from the 2015 NAB AFL Draft to take his place.

"Good way to start training on a cold morning like today (Thursday)," Sier told collingwoodfc.com.au.

"It's something I've been waiting for, for a long time, so I guess there's a bit of relief.

"Now I get to officially call myself an AFL player."

Sier collected 28 disposals, nine clearances, nine tackles and a goal in the VFL last Sunday.

Sier struggled with professionalism earlier in his career.

"By his own admission, (he) probably didn't have football high enough in his priorities in the first 18 months (at the Pies)," coach Nathan Buckley told AFL.com.au in February.

"The last half of last year Brayden really knuckled down and saved his career at Collingwood in many ways, and showed the club that he was serious about being an AFL footballer. So he earned another year on his contract.

"His diligence in pre-season has been really strong. He's still building strength in his body but he's starting to show us the signs that he was drafted for – very clean inside, clean ball-handler, great vision."

Sier, 20, recently signed a contract to keep him at the club until the end of 2019.