Bayer Leverkusen sporting director Rudi Voller says that Chelseatarget Kai Havertz will only leave the club this summer if certain clear conditions are met.

Standard Sport understands that Frank Lampard hopes to seal a £70million deal for the German international following Leverkusen's exit from the Europa League quarter-finals at the hands of Inter Milan.

Havertz was on the scoresheet during the last-eight clash in Dusseldorf on Monday night, but goals from Nicolo Barella and Romelu Lukaku condemned Peter Bosz's side to an exit from European football's secondary club competition.