Di Matteo admits the decision leaves them short for the Carling Cup.
"Gianni hasn't figured in our team much and I think it is always best for the players to go and play rather than just play reserves games," he told the WBA website.
"It means we'll have to shift things around a little bit in the cup.
"But that's the way we have to work to balance certain things.
"Also, the players want to go and play.
"That's how we have to look at it sometimes."