Nevertheless, Sabatini says that the Dutch midfielder, who suffered a knee injury in March that ruled him out of Van Gaal's World Cup squad, is poised to stay in the Italian capital.
"He is an extraordinary player, and these rumours [of his sale] have been based on the desires of other clubs," Sabatini told reporters.
"We want to keep him, he is our point of strength. Of course he is unsellable, but we must contextualise that I do not say he is for sale. We receive offers, protect him and defend him, but I do not know what will happen.
"For now we enjoy him even whilst he is injured. We are not thinking in any way of selling him, we hope to have him return. We must have patience and wait."
Strootman, whose Roma contract expires in 2018, scored five goals and bagged six assists for the Giallorossi in Serie A last season.