The Brazil international is also wanted by AC Milan and Tottenham ahead of the January market.
Sabatini told Romanews.eu: "We wanted Casemiro in the past because there was a time when we could take him under certain conditions. Under the conditions currently this is impossible.
"Rafael, instead, we've never considered. Roma does not need a goalkeeper: (Maarten) Stekeleburg is extraordinary and will defend the Giallorossi goalkeeper in the coming years."