Abraham Papali'i will miss the first two games of Connacht's Heineken Champions Cup campaign.
The flanker's been suspended for five matches following the red card he received in last week's win away to Zebre.
Papali'i was dismissed for a perceived high tackle on Zebre's Tommaso Boni during the second half of Connacht's 47-12 victory.
The 27-year old faced a disciplinary panel yesterday, where it was judged the red card was warranted and a six-week ban be imposed.
— eir Sport (@eirSport) November 22, 2020
A week was chopped off the suspension due to Papali'i's "co-operation throughout the process and remorse shown."
The New Zealand native won't be free to play again until December 28.
Papali'i will miss Sunday's visit of the Ospreys to the Sportsground in the Guinness PRO14, and the following week's clash with Benetton.
Perhaps more crucially, he'll be absent for the Heineken Nations Cup pool matches with Racing 92 (December 13) and Bristol Bears (December 20).
He must also sit out the first of the seasonal inter-pro games with Ulster in Galway on December 27.
Tom Farrell is also unlikely to feature before the new year. He's to see a specialist after picking up a knee injury last week.
Full-back Stephen Fitzgerald is aiming for a January return after undergoing a minor procedure on a knee injury.
But in better news, Caolin Blade (hamstring) and Tiernan O'Halloran (adductor) will integrate into squad training next week.
Paul Boyle captains the province for the first time in Sunday's game with Ospreys.
He's joined in the back-row by Sean O'Brien and Conor Oliver.
Peter Sullivan comes into the team on the wing while Conor Fitzgerald has been selected at out-half.
Connacht team v Ospreys:
15. John Porch, 14. Peter Sullivan, 13. Sammy Arnold, 12. Tom Daly, 11. Alex Wootton; 10. Conor Fitzgerald, 9. Colm Reilly.
1. Denis Buckley, 2. Shane Delahunt, 3. Jack Aungier; 4. Eoghan Masterson, 5. Gavin Thornbury; 6. Sean O’Brien, 7. Conor Oliver, 8. Paul Boyle.
Replacements: 16. Jonny Murphy, 17. Paddy McAllister, 18. Dominic Robertson-McCoy, 19. Cian Prendergast, 20. Jarrad Butler, 21. Stephen Kerins, 22. Sean O’Brien, 23. Colm de Buitlear.