According to a report from La Gazzetta dello Sport, Roma will start bidding for the Villa midfielder if an agreement with Arsenal for Xhaka is not reached.
Roma have reportedly been monitoring Luiz for several weeks, and he is next on the shortlist if a move for Xhaka falls through.
The Giallorossi proposed a €14/15 million offer for Xhaka, yet Arsenal have rejected this, wanting more for the Swiss international.
As a result, Roma are counting on Xhaka's willingness to move to the club and be managed by Jose Mourinho, and while they will be patient as he is their top choice, they will not allow things to drag on for too long.
Luiz's consistent performances for Villa over last season have led to him being targeted as a possible option for Roma.
However, since Villa signed him for €16.8 million from Manchester City in 2019 and he is six years younger than Xhaka, he will probably cost more than Xhaka, with his value reportedly being higher than €20 million.
The new midfielder, whether Xhaka, Luiz or any other signing, will most probably take Amadou Diawara's spot in the team as a defensive midfielder.
Luiz racked up 34 appearances in all competitions last season, even getting three assists as Aston Villa finished in eleventh in the Premier League.
Mourinho reportedly wants to overhaul Roma's squad, looking to make them more solid defensively, with them conceding the most goals in the Top 10 in Serie A, conceding a staggering 58 goals.