The midfielder has been linked with a move away from Stamford Bridge following a limited run in the first team.
However, Di Matteo has made it clear that the 21-year-old is very much a part of his plans.
"Romeu is a very young talent with good prospects for the future," the Italian told reporters. "He has offers from other clubs and especially from Spain but I have had calls from Italy as well.
"But he has been playing a bit more lately and he will be playing more in the future. There is absolutely no chance of him leaving in January."
Romeu has scored one goal in four appearances for the Blues this season.