Reports suggest the Blues have contacted Leverkusen regarding the availability of the 20-year-old, who could cost as much as €100m.
The German international has been in superb form in the Bundesliga this season, scoring 11 goals and assisting five more. His performances have made him one of only nine players in the world who currently hold a perfect form rating of 99 on FootballCritic.
Though Havertz has regularly been linked with a move to one of Europe’s elite, his recent upturn in form has seen the rumours intensify, which has led to Voller commenting on his future.
“We haven’t given up hope that he’ll stay with us,” the Leverkusen chief told ARD.
“He did an outstanding job in the second half of the season.”