Broncos warn Gotsis to bulk up

The Denver Broncos have issued a stern warning to their Australian defensive end Adam Gotsis to bulk up in the NFL off-season or get the axe.

Melbourne's Gotsis is no minnow, standing 193cm tall and weighing 130kg, but he struggled to assert himself among the giants of the NFL in his 2016 rookie season.

Broncos' defensive line coach Bill Kollar has been one of Gotsis' strongest backers, but admitted the Australian "wasn't as far along as we hoped he would be".

"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.

"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.

"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, who lobbied Broncos general manager John Elway to draft Gotsis in the second round of last year's NFL Draft, acknowledged Gotsis was recovering from a torn anterior cruciate ligament in his rookie season.

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