Sky Italia says Barca asked after the defender in talks with Milan over the departure of Jean-Clair Todibo.
While there's no immediate plans to sign the Italy international, Barca have him on their list of potential future additions.
Romagnoli is attractive to Barca management as he can play at centre-half and also on the left-side of defence.
Meanwhile, a move to Milan is now close to Todibo after he held face-to-face talks with Rossonero chief Ricky Massara last Friday.
The deal is expected to be for an initial six-month loan.