ADELAIDE second-year forward Wayne Milera has had a minor hiccup in his quest to force his way into the Crows' star-studded attack, with a knee injury interrupting his pre-season.

The 19-year-old showed some promising signs in playing eight games in his debut season last year.

Milera is poised to play a bigger role either in the forward line or spending time on the wing as the Crows look to add pace to their midfield. 

However, Crows star Eddie Betts – who on Wednesday re-signed with the club until 2020 – said Milera had been restricted in the amount of training he was able to do. 

"Wayne's still off the track at the moment and he's doing some running on the sidelines," Betts said. 

"He's had a slight setback with his knee, but he's coming back into drills." 

The Crows selected Milera with the 11th pick in the 2015 NAB AFL Draft. 

He debuted in last year's season opener against North Melbourne at Etihad Stadium before having 20 possessions and nine marks in the Crows' 58-point thumping of cross-town rivals Port Adelaide in round two.

After playing the first four games of the season, Milera returned to the team in round eight, making another four appearances.

He averaged 11.1 possessions and 3.1 marks in his eight games.