GEELONG midfielder Jimmy Bartel may have suffered a medial ligament injury in his left knee on a dramatic day for the Cats at Simonds Stadium.

The 31-year-old will undergo scans to reveal the extent of the injury however he looks set to miss at least the next month if those fears are realised.

He hurt is knee when Suns midfielder Michael Rischitelli slid low to win a contested ball and his knee bent under pressure.

"Bartel is definitely medium term. He won't play in the next couple of weeks,” Coach Chris Scott said.

The Cats are also sweating on veteran midfielder Mathew Stokes, who hurt his ankle before half-time and played no further part after the main break.

The injury is understood to be related to his Achilles, however the club was going to wait for scans to determine the extent.

Scott said Stokes was unlikely to play next week against North Melbourne.

Tom Lonergan was lucky to escape neck damage after copping a knee to the back of his head in a marking contest late in the third quarter.

He was taken from the ground on a stretcher and later cleared of neck damage although he appeared to have suffered concussion.

The 30-year-old will be monitored and a decision on his availability for round four is likely later in the week.

Scott preached caution against an early diagnosis being made on any player who suffers concussion.

"One thing I will say about Tom's situation is if you're a so-called external expert, I think you should be really careful around the issues around concussion for individual players when you've never set eyes on them," Scott said.

"If you want to help, come in and see him face to face, get a feel for the situation, speak to the experts that we have internally before you spout off for self-indulgent reasons."