Manchester United are reportedly desperate to bring either Napoli's Kalidou Koulibaly or Inter Milan's Milan Skriniar to Old Trafford as part of a defensive revamp.
According to The Independent, the two names now on United's list are Koulibaly and Skriniar, with both seen as long-term options for the club.
Koulibaly, 27, is widely regarded as one of the best central defenders in world football and has previously been the subject of a £95m bid from United, according to Napoli president Aurelio De Laurentiis.
Skriniar, meanwhile, joined Inter from Sampdoria in 2017 and the 23-year-old has made 63 appearances for the Italian giants in all competitions.
United have conceded 32 goals in their 21 Premier League matches during the 2018-19 campaign.