Greater Western Sydney's Lachie Whitfield in action during round 14, 2021. Picture: AFL Photos

GREATER Western Sydney's Lachie Whitfield will miss Saturday's Sydney Derby XXI after being diagnosed with a concussion following the match against the Suns in Ballarat on Sunday.

Whitfield came from the field in the second quarter with visual disturbance, had a head injury assessment and was ruled out of the game.

The 26-year-old has a past history of migraines following head knocks. 

After exhibiting further symptoms following the match and undergoing a concussion test on Monday, Whitfield was diagnosed with a concussion and will now undergo the mandatory 12-day concussion protocols.

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GIANTS Head of Medical Cullan Ball said:

"Lachie obviously got a knock and he’s had some migraine-type symptoms over the course of the last couple of years and that has led to some visual disturbances for him and that’s what happened to him during the game.

"Unfortunately for Lachie his symptoms deteriorated as the quarter wore on and ultimately he was ruled due to those visual disturbances.

"At that point he was sent to hospital for observation and some further investigations to ensure he didn’t have a facial fracture. Thankfully those investigations came back clear. 

"He checked in with the medical staff again today and had his concussion assessment, which he failed, so he’s now been classified as a concussion and will enter the return-to-play protocols and we’ll see how he progresses over the next couple of weeks."