The star Cat, who is expected to be right up there in the race for the prestigious medal, was cited for making contact with his head to Docker nemesis Crowley.
The incident was assessed as reckless conduct (two points), low impact (one point) and high contact (two points), which drew a total of 125 demerit points.
He could have escaped with a reprimand, but a 30 percent loading due to a bad record and carry-over points meant the Cats would have risked a two-match ban had they challenged and lost at the trigunal.
The early plea means Johnson will miss Friday night's clash against North Melbourne and still have 75.31 points hanging over his head.
Melbourne will be without in-form forward Chris Dawes for their Round 11 match against Port Adelaide after he accepted a one-match ban for strking Richmond's Chris Dawes.
Fremantle's Zac Clarke will have 93.75 points to his name for the next 12 months after accepting a reprimand for striking Johnson.