Gloucester must wait on the fitness of Mike Tindall, Olly Morgan and winger Matthew Watkins before confirming their team to face Cardiff Blues in tomorrow's key Heineken Cup pool clash.

All three remain doubtful, but will undergo fitness tests today ahead of tomorrow's Pool Six clash at Kingsholm.

Centre Tindall has been troubled by a dead leg this week, while full-back Morgan dislocated his finger in last weekend's 10-7 Guinness Premiership defeat at Newcastle and winger Watkins has a leg injury.

Willie Walker, Anthony Allen and the fit-again James Simpson-Daniel – three months after he made his last appearance for Gloucester, also against Cardiff – stand by to replace them.

If all three are declared fit, Simpson-Daniel will start the match on the bench having recovered from ankle surgery.

There is also a return for Iain Balshaw, who will start on the wing after missing six games with a groin problem. He scored two tries when Gloucester were beaten 37-24 by Cardiff at the Millennium Stadium in October. Head coach Dean Ryan, whose side trail Cardiff by four Pool Six points, knows there is no margin for error when the Welsh side visit tomorrow.

"We understand that if we want to continue in Europe then this weekend is absolutely vital," he said.

"I think we are a pretty robust outfit and we need to take that into this weekend.

"We did some pretty smart things in attack against them earlier in the season but they scored twice far too easily just before half-time – that is something you cannot afford at this level because it is so hard to go back and repair any damage. I am confident that if we are slightly more solid our attacking game will offer us opportunities we must try to exploit.

"Heineken Cup weeks are quite easy – there is no motivation required, there will be a lot of emotion and players respond to that. We are at home and we will be fighting for a result.

"There have obviously been some injuries this week and we have to try and work through that in a positive way."