Sonny Bill Williams has been suspended for four weeks following his red card in the second Test against the British & Irish Lions.
The All Blacks centre was given his marching orders by referee Jerome Garces in the 25th minute of Saturday's clash in Wellington, after a shoulder charge on Anthony Watson.
Williams was hit with a ban when he appeared before a three-man judicial panel in Wellington on Sunday, with the New Zealand Rugby Union announcing a verdict that means he misses next weekend's Test series decider.
After the hearing, Williams gave his reaction, which was posted in a series of tweets published on the All Blacks' official Twitter account.
The 31-year-old said he was "really disappointed, but happy with being able to get in there and say my piece".
He added: "They've come to the conclusion that it was reckless, it wasn't intentional. "I've got in contact with Anthony, and I've apologised to him."
And in a final tweet, Williams added: "...but very disappointed that I was sent from the field last night and let my brothers down."
Ahead of Williams' hearing outcome, the All Blacks called up centre Malakai Fekitoa to their squad ahead of the Lions clash in Auckland next weekend.
But the loss of Williams will be a major blow as New Zealand look to prevent the Lions from recording a first series victory over them since 1971.
Speaking in Wellington before the hearing, New Zealand head coach Steve Hansen said that World Cup winner Williams knows he let the All Blacks down with his sending off.
The Lions' 24-21 victory consigned New Zealand to a first defeat on home soil since 2009, ending a 46-match unbeaten run, while the All Blacks have not lost successive Tests for six years.
New Zealand's next fixture after the Lions decider is a Rugby Championship clash against Australia on Aug. 19.