The same report says that West Ham United are willing to listen to offers for the former Manchester United striker, and that re-signing him would be easier for the Red Devils than trying to land Sanchez or Vardy.
Sanchez is still likely to move to Manchester City so United could be on the lookout for other striking options.
Leicester's Vardy would be the most expensive option of the three at around £35m, despite the England worldwide turning 31 today. He would also be eligible to play for United in the UEFA Champions League.
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They will need to show that against the likes of Calais Campbell , Yannick Ngakoue , Dante Fowler , Jr., Myles Jack and company. All of that is happening while Vance McDonald and Marcus Gilbert are shuffling in and out of the lineup with their issues.
And according to the Telegraph's James Duncker, Man United have made preliminary enquiries for Vardy and Hernandez, with the latter firmly on the periphery under David Moyes.
Hammers manager David Moyes does not rate Hernandez - just as he didn't when he was United boss in 2013/14 - and is getting ready to sell the Mexican just six months after he was signed from Bayer Leverkusen for £17m.
The Mexico global scored 59 goals in 158 games, often from the substitutes bench, during four years at Old Trafford and has a scoring rate in all competitions for club and country of a goal every 2.4 matches.
Per Wallace, Hernandez is not wanted at West Ham United, while United manager Jose Mourinho has said previously he would not have allowed him to leave Old Trafford.