Following the Roosters Round 7 clash against the Newcastle Knights, one member of the first-grade squad has been added to the injury list.

Ryan Matterson was forced from the field after sustaining an ankle injury early in the second half and was unable to return.

Scans have confirmed over the weekend that he has ankle ligament damage, which is less serious than what was expected.

Matterson will be sidelined for 4-6 weeks while he recovers.

The rest of the squad made it through the match unscathed and will be available for selection against the St George-Illawarra Dragons on Anzac Day.