THREE Melbourne clubs suffered injury blows at the weekend in NAB Challenge action.

Carlton will know the extent of Andrew Walker’s injury late on Tuesday after the midfielder injured his right shoulder in the club's practice match on Friday against the Western Bulldogs.

It was the 21-year-old’s second pre-season game this year. He missed three games because of the same injury last year.

Hawthorn also had a scare with Campbell Brown limping off the field just minutes into the Hawks’ NAB Challenge clash with Collingwood in Shepparton on Friday night.

The defender, who is suspended until round two of the season proper, is not expected to spend any longer than that on the sidelines.

In other injury news, Geelong defender David Wojcinski will be out of action for three to four weeks, ruling him out of the start of the Cats’ premiership defence.

Wojcinski underwent surgery on a tendon in the little finger of his right hand on Monday after he suffered the injury in Friday’s practice match against Richmond.