Both Chelsea striker Lukaku and Bologna ace Zirkzee are being considered by Milan this summer.
Crespo told La Gazzetta dello Sport: “Zirkzee is a player for the future, whereas Lukaku seems more suited to the immediate situation.
“To put it bluntly, the Dutchman has huge margin for improvement, while we already know the veteran’s qualities. Not all centre-forwards are the same, just like I was not similar to Gabriel Batistuta, which is why we could play together for Argentina.
“Zirkzee likes to drop deep and dialogue with his teammates, but also has strong physicality needed to protect the ball. Lukaku is more old-fashioned, not in a negative way, and is more of a battering ram. He is also deadly on the counter-attack and dictates the through ball to get the whole team moving.”
The Argentine continued: “The issue is that Milan need goals straight away and the fans at San Siro don’t have time to wait around.
“Zirkzee had a good season at Bologna with 11 goals, whereas Lukaku wasn’t that sharp at Roma, but if he’s in good shape physically, then he guarantees goals. I don’t know how Zirkzee would handle such a big club and stadium. Bologna is not Milan. Lukaku is more accustomed to that stage.
“If the wingers are Christian Pulisic and Rafael Leao, then Lukaku is perfect to get on the end of their crosses. Zirkzee prefers to complete these triangles and dialogue with his teammates. Considering how Fonseca’s teams played in the past, perhaps the Belgian is better suited.”