The 29-year-old was forced off during Saturday's 2-1 loss to Hull City with a knee injury.
However, McCarthy has revealed that the midfielder is "optimistic" that he will shake off the knock in time for the match at Portman Road.
"He's recovered pretty well actually. The swelling has gone down and he'll be fit for Saturday and we hope he'll be okay for tomorrow as well. He's quite optimistic," the East Anglian Daily Times quotes McCarthy as saying.
Tabb joined the Tractor Boys on a loan deal from Reading last month.