Striker Alan Lee and midfielder Matt Richards are both making good progress after the groin and ankle injuries they suffered at the end of last season. Lee, who recently underwent abdominal surgery, could be back in action on the pre-season tour, while Richards is close to a return to full training.
Town's head of sports science Dave Williams told the club site: "Alan is doing well and will now start his pre-season work with fitness coach Simon Thadani.
"He will work with Simon for the next week or two and at the end of that time we will be in a position to judge his recovery.
"It's looking encouraging at the moment though, and he has not been ruled out of the tour yet.
"If we think he has a chance of playing in maybe the third game against FC Brussels then there is a possibility Alan will travel, but it will be down to what the manager says after we have looked at him."
Williams says that Richards is also doing well: "Matt is well on the way now and will be back in full training over the weekend or next week.
"He has had a good week and will step his recovery up now, but is naturally one of the fittest players at the club anyway.
"Fitness-wise he's probably in the middle of the pack at the moment but, with the extra work he will be putting in, he'll be up in the top three in time."