Northampton’s Curtis Langdon has been suspended for four weeks after being sent off in their Investec Champions Cup win at Munster on Saturday.
The hooker was shown a red card for reckless contact to the head of Tom Ahern, who was forced off injured.
An independent disciplinary committee upheld the decision and determined Langdon should be sanctioned for striking with the knee.
The offence could have resulted in an eight-week ban.
However, the committee took the 26-year-old’s guilty plea and clear disciplinary record into account and reduced the sanction by the maximum of 50%.
Despite being reduced to 14 men in the first half, Northampton fought back to beat Munster 26-23 at Thomond Park and extend their lead at the top of Pool 3.
The Premiership leaders host bottom-placed Newcastle Falcons on Saturday.
Nottingham said Langdon’s return date will be decided “when the independent disciplinary committee has received full details of his future playing schedule”.