Judicial officer Sheriff Mackie had originally requested a 10-game ban for O'Toole's challenge on Nankivell, which resulted in the Munster centre suffering a hamstring injury.

In a statement published on their website, the URC explained that O'Toole received 40% mitigation for his "admission of foul play, immediate apology and again post-match".

However, because O'Toole previously received a red card for "foul play" against Toulouse in 2022, "not all mitigating factors were applied".

Interim head coach Simon Easterby said in the URC's statement that O'Toole would have "barring injury or suspension, a very good chance of being named in the matchday squad" as he had been "a constant member of the Ireland senior squad since debut in 2021".

As a result, the URC felt that it was "appropriate" to include Ireland fixtures in the ban.

After the England and Scotland games, Ireland face Wales away, France at home and finish against Italy in Rome as they seek to win a third successive Six Nations title.

Easterby, who takes interim charge of Ireland as Andy Farrell prepares to lead the British and Irish Lions in their tour of Australia in the summer, will name his Six Nations squad on Wednesday 15 January.