Bath Rugby have confirmed that Wales and British and Lions number eight Taulupe Faletau has broken his arm.
The 27-year-old sustained this latest injury setback during Bath's Gallagher Premiership defeat to Exeter Chiefs last Friday, leaving the field during the 67th minute of the 24-39 loss.
Bath have not yet confirmed an estimated recovery time, but the 72-times-capped Welsh international is likely to miss the November Internationals, in which Warren Gatland's side will face Scotland, Australia, Tonga and South Africa, in addition to Bath's Champions Cup campaign over the next two weeks.
Faletau also missed a significant chunk of the 2017/18 season with a knee injury, missing Wales' fixtures against Scotland, England and Ireland during the 2018 Six Nations.
Bath will likely turn to promising youngster Zach Mercer, who has featured to blindside flanker over the last few rounds of Premiership action to allow both himself and Faletau to enter Bath's starting XV.
Meanwhile, Gatland looks set to once again turn to Dragons and former Gloucester flanker Ross Moriarty, who has played in the Welsh eight jersey during Faletau's aforementioned absences.