The United States international arrived in Turin on loan from Schalke under previous boss Andrea Pirlo last summer before making the move permanent in an €18.5 million deal in March. However, Tottenham Hotspur have been linked with a move for McKennie this summer.
“He doesn’t have to leave. He has goals in his legs,” Allegri said in a news conference on Friday. “He must improve, he’s an attacking player and we are in very good shape in this department.”
McKennie, 22, scored six goals in 46 appearances in all competitions last season as Juve failed to win the Serie A title for the first time in a decade.
Ronaldo left Italy early Friday morning as sources told ESPN that Juve and United agreed to a €15 million deal with a potential further €8m in add-ons for the Portugal star’s transfer.
When asked how his side will deal with the departure of Ronaldo, Allegri added: “They are already all responsible, it’s normal that now, with the absence of Cristiano… they are all responsible, there are many young players and we need to improve from all points of view.
“The difference will be how quickly we arrive at a right mental aspect, that allows us to win games and manage them in moments like we faced in Udinese.”