A number of complaints have restricted Mowbray from selecting what is perceived to be his best back four for the majority of 2013.
Discussing the ongoing situation, Mowbray insisted that while he is concerned, there is not much he can do about it.
"It's becoming a concern. To lose three at Derby, four at Ipswich and then four again at Palace, it's a worry," he is quoted as saying by the Northern Echo.
"Yet there are personnel reasons. I could give you our first-choice back four, and at the minute, you'd have to say that three of them aren't playing. That's football and you have to get on with it. The squad is only ever as strong or as weak as the numbers underneath what you would call the first 11. That's what football is.
"If we've got Hoyte, Woodgate and Hines injured, you have to take it on the chin and get on with it. Unfortunately, I don't think any of them will have a chance for Tuesday."
Boro have conceded 50 goals in 32 Championship matches this season.