Williams became the first New Zealand player in 50 years to receive a red card, sent off by referee Jerome Garces in his side's 24-21 second-test loss to the Lions.
The 31-year-old was sent off in the 25th minute after a bruising shoulder charge that struck Lions winger Anthony Watson flush in the face.
The tackle proved a pivotal moment in the match with All Blacks coach Steve Hansen having to rejig his starting XV to accommodate for the send-off.
Williams pleaded guilty to unnecessary contact to the head.
