The Reds carry a one-goal lead from the first leg thanks to a strike from Jordon Ibe but given the vulnerabilities in the Liverpool defence, Aldridge feels that the Potters will find the net at Anfield tonight.
He wrote in his Liverpool Echo column: "It’s a big night for the defence and those defending, trying not to give away soft free-kicks or needless corners, and then dealing with them when they come in.
"Every scout will have seen what we see - that Liverpool can’t defend set plays. Mark Hughes will be trying to get his players to gain little advantages in the last third.
"They’ve got some big, tall players to hit in the area too.
"But we defended well at their place and a clean sheet gets you to Wembley - as a defender there’s no better inspiration than that."
Liverpool managed to deal with everything Stoke threw at them in the first leg at the Britannia Stadium with a centre-back partnership of Kolo Toure and Lucas Leiva for large parts. It shows there is an element of defensive resolve somewhere in this Liverpool side and it is something they may need to find this evening.
But, as Aldridge also says, Liverpool have got to set up to go out and win the game. The onus will be on Stoke to try and overturn Liverpool's lead but given the Reds' recent record, they can hardly sit back and just invite Stoke onto them.
It will be interesting to see how they approach the game, and what changes, if any, that Jurgen Klopp will make to his side in order to secure their passage to Wembley.