Midfielder Gavin Williams will undergo scans and an x-ray after complaining of a pain in the pelvic region having limped off in the second half of Tuesday's 0-0 draw at Stoke. Prior to the new problem, the Welshman was pleased with the way his groin injury was progressing.
Town's head of sports science Dave Williams told the club site: "Gavin said that he was feeling much better and there were signs that things were improving.
"He came off against Stoke though, and says that he has a new pain in the pelvic area, so we are treating it as a new injury.
"He is having scans and x-rays tonight and doing some tests and then we will take it from there.
"It's obviously a concern but we will know much more when we see the results of the scans on Thursday."
French midfielder Sylvain Legwinski has a slight hip problem but is not expected to miss Saturday's trip to Crystal Palace. Striker Alan Lee was absent for last night's game due to a hamstring injury but could be back for the match at Selhurst Park.
Meanwhile, last night's stand-in skipper Fabian Wilnis has revealed that Luton Town, Millwall, Huddersfield Town, Port Vale and Bristol City were the clubs interested in taking him on loan earlier in the month.
The 36-year-old told a Dutch magazine that he had asked to go out on loan for a month after falling out with boss Jim Magilton, having been blamed for Town's home defeat to Preston earlier in the season.
Wilnis hopes to win another one-year contract at Portman Road and a testimonial. The former De Graafschap man made his 300th appearance for Town at Stoke.