Rio Ferdinand was Rooney's teammate at Old Trafford.
The French midfielder joined United in the summer.
"Everyone thought he needed to learn," former United captain Rio Ferdinand said of Ronaldo.
Rooney was below par again in the League Cup win over Northampton Town.
The former England captain aims to get into coaching.
The former United defender played alongside the Frenchman.
Nemanja Vidic was a rock in Sir Alex Ferguson's defense.
He departed for Juventus in 2012.
He wishes United had snapped up the former Barcelona manager instead.
Rio Ferdinand and Paul Scholes did not hold back.
Regan Poole plays in the style of the cultured defender.
The Portuguese winger was in sharp-tongued mood before the game against A.S. Roma on Wednesday.