The England international is on-loan to the end of this season.
Ahead of facing Roma, Pioli said: "He is doing well, has good characteristics and has entered with great speed.
"We will see if he will play from the first minute tomorrow.
"Apart from (Mario) Mandzukic, (Daniel) Maldini and (Ismael) Bennacer, they are all available. We will try to make the best choices."