Bath captain Ben Spencer is a doubt for Sunday's Investec Champions Cup semi-final against Bordeaux in what could be a major test of the club's depth at scrum-half.
The England half-back has not played since the last-eight victory over Northampton on 10 April because of a shoulder injury and alongside Cameron Redpath, Max Ojomoh and Joe Cokanasiga is rated 'touch and go' for the trip to France.
Adding to the concern at nine is that Bernard van der Linde has undergone surgery on the ankle injury he sustained in Saturday's narrow loss at Northampton.
It means double-chasing Bath could enter their biggest match of the season so far with Tom Carr-Smith as the senior scrum-half and 18-year-old rookie Isaac Mears providing back-up.
Mears has yet to make his senior debut for the club and only signed his first professional contract this month.
'Bernard had his operation on Monday morning and we hope to get him back before the end of the season,' Johann van Graan said.
'You've got to be adaptable. I thought Tom Carr-Smith was exceptional against Northampton on Saturday.
'Isaac Mears is the next nine in and we've pulled him out of the England Students, so he's in the group.
'One of the bits that obviously the group knows but the outside world doesn't is that we go through multiple situational plays and training sessions throughout the year.
'So let's just say in a worst-case scenario, you might see somebody play at nine who has never played at nine. There are many different things we could do.
'What we've consistently done for three years and 10 months is back our squad.'
The injured contingent will be given until Friday's training session to prove their fitness, with the team to be named that same day.
