The 19-year-old was regarded as one of the brightest prospects in European football when he moved to Bayern last summer, but he made just six Bundesliga starts last term and his progress appears to have stalled.
AC Milan were thought to be on the verge of a £35m deal for the Portugal international, but Rummenigge suggested that they will only allow him to leave on loan, with Chelsea one of a number of clubs interested in his signature.
"There are at least 10 teams after Sanches. Conte asked for some information about him after Tuesday's match because he knows he can make the difference in the middle of the pitch," he told Italian newspaper La Gazzetta dello Sport.
"The lad wants to play regularly but [Carlo] Ancelotti was pleased with his performance against Chelsea . We'll make our evaluations later but if he does leave then he almost certainly will go on loan. We're still counting on him."
Sanches made 25 appearances for Bayern across all competitions last season.