Luckless Adelaide defender Wayne Milera has suffered a suspected patella tendon rupture and is likely to miss a majority of the 2021 season.

The 23-year-old sustained the injury in the Crows' practice match against Port Adelaide and was assisted off the field in the second quarter.

The injury is a further setback to Milera's young career after the flashy defender suffered a stress fracture in his foot last season, requiring surgery an limiting him to just the two matches for the year.

Milera has played just the 62 matches since joining the Crows via the 2015 draft and was in line for a move into Adelaide's midfield this season.

“I’m training with the midfield group at the moment,” Milera told AFC Media last month.

“It’s where I want to play down the track and I feel I can add a lot to that group.

“I like playing off half-back, but as an AFL footballer you need to be able to play in a few places.

“I want to be in the thick of things, that’s where footy games are won and lost.”

Milera will undergo further assessment and scans in examining the extent of the injury.