HAWTHORN remains confident Grant Birchall will be available for the latter part of the NAB Challenge despite the defender missing four to six weeks due a knee injury.

The 27-year-old damaged his medial ligament during a tackling drill at training last week and has already been ruled out of the Hawks' opening pre-season clash against Collingwood at Aurora Stadium on February 26.

It is the second time in two years Birchall has suffered a knee injury with the All Australian missing seven weeks of the 2013 season after damaging his posterior cruciate ligament.

The three-time premiership player won't begin a running program until Monday but the Hawks still expect him to feature in the NAB Challenge.

Hawthorn meets North Melbourne at Deakin Reserve on March 8 before facing St Kilda at Etihad Stadium on March 19.

The Hawks open the premiership season with the traditional Easter Monday blockbuster against Geelong April 6.