WESTERN Bulldogs forward Clay Smith will miss at least the next month with a knee complaint.

The premiership star was absent from the club's JLT Community Series campaign and didn't take part in the club's intra-club hit-out.

The 24-year-old appears to be struggling with the right knee he's had reconstructed three times in his seven-year career at Whitten Oval, and he trained away from the main group on occasions last week.

The hard-tackling forward was crucial to the club's 2016 flag triumph, kicking eight goals and adding fierce forward pressure in the Dogs' memorable run through September.

As well, coach Luke Beveridge's injury-hit defensive stocks will have to do without Kieran Collins for at least another month, as the third-year stopper is still recovering from ankle surgery in November.

Standing at 194cm and 100kg, Collins made his debut in round nine, 2016, but hasn't featured at senior level since and was only offered a one-year contract extension at the end of last season.

An All Australian at under 18 level, the Dandenong Stingrays product arrived at the Whitten Oval with pick 26 in the 2015 NAB AFL Draft.

Collins joins fellow key defenders Dale Morris (knee) and Marcus Adams (ankle) as players unlikely to be available until mid-season.

Running defender Hayden Crozier injured his knee in the loss to Greater Western Sydney and will spend up to a month recovering.