Wasps forward Nathan Hughes has been banned for three weeks by an RFU Disciplinary Panel following an incident that led to Northampton's George North being knocked unconscious.
The 23-year-old was sent off for his challenge on the winger, who was scoring Saints' second try on Friday.
A panel found Hughes guilty of "striking with the knee and/or shin".
"This was a three-week ban on the basis that no intention was found," said Sir James Dingemans, chair of the panel.
He added: "However, there was recklessness meaning that, notwithstanding the harm, it was a low entry point of four weeks with mitigation of one week to reflect his previous clean playing record."
Wales international North is due to see a neurosurgeon to determine when he is able to play again.
North, 22 has been knocked unconscious three times in recent months.