The good news for the Tigers is that England and Lions lock Ben Kay is fully fit and will come into contention along with lock Louis Deacon and old stager Austin Healey.
Meanwhile, Wells, who played the 1997 semi-final between the two clubs at Welford Road is expecting a fantastic occasion as the Walkers Stadium hosts its first rugby game in front of a full house of 32,000.
"This game could 9-6 or 40-30. That's the quality of the side we are playing," said Wells.
"We are under no illusions about the opposition. Toulouse are capable of winning the Heineken Cup and the French Championship title.
"They are a joy to watch, but they are also capable of losing because of the style they adopt.
"In the final last year at Twickenham they ran London Wasps around the field all afternoon. But it was Wasps defence, and a little bit of luck, that won then the title in the end.
"Toulouse have the best set of club backs in Europe. If they get the right ball to set their backs rolling then they are going to be a handful.
"But Toulouse always have the ability to shoot themselves in the foot and we have to be ready and well prepared to meet them.
Leicester Tigers squad to face Toulouse:
Martin Johnson (captain)