The Croatia international has generated intense speculation throughout the summer transfer window.
Jose Mourinho was reported to have identified the 28-year-old as a top target, with United eager to bring in further attacking reinforcements.
Inter have sought to rule out any deal, as they seek to tie Perisic to fresh terms at the San Siro, but Crespo believes that a move could be made to the Premier League if the right offer is tabled.
The former Inter and Chelsea striker told The Express: “It's possible he joins Chelsea - but he plays on the left and on the left you have Eden Hazard, Perisic and Marcos Alonso.
“Maybe he could come in through the middle or to the right.
“Perisic is a good player but I don't know if Inter wants to sell. I think 'no' but it depends on money. It's always the same. It depends on money.
“If you put a lot of money down, even Inter will sell him, but they don't want to sell him.”
Regardless of whether a move for Perisic is made, Crespo believes that there will be further movement at Stamford Bridge before August 31, with Antonio Conte needing to bolster his ranks after seeing permanent sales and loan exits deplete his senior squad.
“He needs signings if he wants to repeat and win the league," Crespo added.
“He did a great job last year but if you want to keep going and win you need to put in two or three pieces.
“Where? It depends on Conte.
“They could do with another striker, for sure. It's true that Alvaro Morata is good but he's a different player to Diego Costa."
Reigning Premier League champions Chelsea will open the defence of their crown at home to Burnley on Saturday.