Chris Ashton will miss England's entire Six Nations campaign after being given a 10-week ban that ends on 28 March.
The Saracens winger, 28, had just been recalled to the England squad, 18 months after his last appearance.
Ashton was cited for making contact with the eyes of Ulster's Luke Marshall in a European Champions Cup game.
England, now coached by Australian, Eddie Jones, begin their Six Nations campaign in Scotland on 6 February, ending it on 19 March in France.
Ashton, who has 39 caps, has the right to appeal against the decision and Saracens are weighing up the decision. They have 72 hours after the written judgement is received to decide whether to lodge an appeal.
Jones said he would wait for the outcome of any appeal before naming a replacement.
He added: "He's been playing well this season and it looks like he has been working hard. Everyone has set-backs and it's about how hard he fights back now.
"He has to serve his time, come back, make sure he is looking after his fitness, his speed and his skills and make sure he comes back in good fettle.
"If he is back on the field and playing well then he will be available for selection again. I'm very disappointed for him and disappointed for the team, but we move on."
According to the judicial officer who ruled on the case, Ashton committed an act of foul play that warranted a red card. The official determined that the offence was at the low end of World Rugby's sanctions and selected a 12-week ban.
He then added one week as a deterrent, according to World Rugby guidelines regarding offences of this nature, before reducing the sanction by three weeks due to Ashton's good character and good conduct.
"It's a huge blow to Chris Ashton," former England skipper Will Carling told BBC Radio 5 live.
"He's worked incredibly hard to get back. When he first appeared, he was outstanding and it would've been great to see him back."
BBC Radio 5 Live's rugby union reporter Chris Jones:
Given how hard he has worked to get back into the international fold, this ban will be a devastating blow for Ashton, who is desperate to resume his England career after falling out of favour under Stuart Lancaster.
Although Ashton's challenge could be considered reckless, it is not malicious and it seems almost certain Ashton will appeal.
However, as things stand, England boss Jones will be without the Saracens wing and will need to call up a replacement.