Gloucester prop Fraser Balmain will be out until December with a knee injury.
The prop suffered a twisted knee in the 28-17 defeat to Harlequins at the Stoop two weeks ago.
The prop, who signed from Leicester Tigers over the summer, has had surgery on his knee and could now be out until just before Christmas.
In addition to Balmain, Ben Morgan is currently out with a calf injury and Matt Scott could be out for a similar amount of time having limped off against Leicester.