Serie A could introduce five substitutions a match, after a request was sent by the Italian Football Federation (FIGC) to football's lawmakers.
The move is backed by Italy's top-flight clubs who want more choice, with teams already allowed to name 12 substitutes on the bench.
The five changes would be made over three stoppages, to reduce the number of breaks in play.
Serie C already allow five substitutes.
FIGC president Gabriele Gravina has sent the request to the International Football Association Board (Ifab).
Champions League and Europa League games permit a fourth substitute in extra-time and it will also be allowed at the 2020 European Championship.
The Football Association announced in 2018 that it would permit an extra substitute in the latter stages of the FA Cup, from the quarter-finals onwards, while the Football League has permitted a fourth substitute in extra-time in all EFL Cup ties since 2017.