Fremantle's Ryan Nyhuis has been handed a three-match ban for his sling tackle on Port Adelaide's Robbie Gray during Sunday's clash at Optus Stadium.

Early in the third quarter, Nyhuis tackled Gray over the boundary line before dumping him into the turf, with the Power star needing to be stretchered off after being knocked unconscious in the tackle.

Nyhuis was referred directly to the Tribunal by Michael Christian on Monday.

The 21-year-old will miss Fremantle's upcoming matches against Essendon, Hawthorn and West Coast.