An embarrassing AFL spelling error has resulted in West Coast defender Eric Mackenzie being suspended a day after accepting a reprimand.

Mackenzie on Tuesday submitted an early guilty plea to striking Fremantle's Michael Johnson, after being initially told the resultant 25 per cent penalty reduction meant he would avoid suspension.

But the AFL informed the Eagles on Wednesday they had failed to count the backman's carry-over demerit points from a previous offence.

That rough conduct offence occurred just 15 days earlier.

But because the league incorrectly entered the Eagle's name as McKenzie, it did not show up on their computer records.

Once the error was corrected, the extra points lifted the penalty to a two-match ban, reduced to one after Mackenzie submitted a guilty plea for the second time in as many days.

It means he will miss Saturday night's battle of the bottom two against Brisbane at Subiaco, which is likely to decide which club gets the wooden spoon.

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