CROWS midfielder Chris Knights has been ruled out for another three to four weeks while he recovers from a quad strain.

Knights suffered the strain against St Kilda in the NAB Cup Grand Final and, because of the nature of the injury, the club was reluctant to put a time frame on the 21-year-old’s return.

The gifted ball winner, who finished in the top 10 in Adelaide’s best and fairest last season, was troubled by a similar injury in 2006, which caused him to miss a string of games towards the end of the year.

Further scans have revealed some improvement, but physical performance manager Stephen Schwerdt said the club wouldn’t take any risks with the young star.

"We will continue to be really cautious with Chris because of the type of injury,” he said.

“If his return is rushed there is a high risk of a re-occurrence so his return to full training will be monitored closely."

Kurt Tippett also sent a scare through the Crows camp after falling awkwardly on his knee during the third quarter against West Coast.

But he ran freely on Monday and the club is hopeful the promising forward will be available this week.

In other injury news, midfielder Rob Shirley trained late last week and looks set to resume after missing last week with a calf strain.

Nick Gill, who has also been troubled by a calf injury, could line-up in the SANFL this weekend.

Brent Reilly (wrist) and Brad Moran (finger) are also at least a month away after undergoing surgery on their respective injuries.