RICHMOND premiership midfielder Shaun Grigg is expected to miss at least the first two rounds of the season with a knee injury.

Grigg, who has also been an important part of Richmond's structure in the past two years by pinch-hitting in the ruck, has a joint issue affecting his ability to train at high intensity.

"Shaun has been doing some good running sessions, but he just needs more time for his knee to improve, so that we can progress his training loads," Richmond's general manager of football Neil Balme said.

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"Given that he's in a bit of a holding pattern with his training, at this stage we think it's unlikely that he'll be available to play in the next four weeks."

The 30-year-old has been incredibly durable since crossing from Carlton at the end of 2010, missing just 13 games in eight seasons.

The untried Noah Balta may be one to take Grigg's pinch-hitting role, having impressed in last week's JLT win over Melbourne.