GRIDIRON: A 130kg frame is not enough for the Denver Broncos when it comes to Australian defensive end Adam Gotsis

The 193cm NFL heavyweight has been given a stern warning by Broncos officials to bulk up or suffer the pain of an axing.

Broncos defensive line coach Bill Kollar has been a strong supporter of the Aussie, but admitted Gotsis "wasn't as far along as we hoped he would be” after his rookie season, which was hampered by a torn anterior cruciate ligament.

"Physically, I've told him all along: 'You've got to get bigger and stronger - or else,” Kollar told DenverBroncos.com.

"These guys are too big and strong and tough in this league."

Dontari Poe, at the Kansas City Chiefs, tips the scales at a whopping 157kg.

"I told him, 'If I were you, I'd take one week off after the season, I'd get my (rear end) into the weight room and I'd lift until there was no tomorrow because otherwise you don't have a chance," Kollar added.

"You've got to be able to get in there and fight.

"Right now, where he was physically, he wasn't where he needed to be.”

Kollar lobbied Broncos general manager John Elway to draft Gotsis in the second round of last year's NFL Draft.

The Broncos won the Super Bowl a year ago, but failed to make the 2016-17 playoffs.