Havertz is now Frank Lampard's top target following deals for ex-Ajax playmaker Hakim Ziyech and prolific striker Timo Werner, with the Blues eager to press ahead with a deal after sealing qualification for next season's Champions League courtesy of a fourth-placed domestic finish secured on the final day of the 2019/20 campaign.
The German international is understood to have informed Leverkusen of his wish to move to Stamford Bridge, with Chelsea targeting a deal that they believe would be worth in the region of £70million.
However, the beaten FA Cup finalists have not been able to strike an agreement before the return of European football as hoped, with Havertz having returned to training with Leverkusen last month following a short post-Bundesliga break and now set to feature for the club in the Europa League.
The German outfit always remained insistent that would be the case, with Havertz poised to line up on Thursday night when Leverkusen face Steven Gerrard's Rangers at the BayArena in the second leg of their round of 16 tie, which the hosts lead 3-1 after a comfortable March win at Ibrox in which the player in question opened the scoring from the penalty spot in the first half.
Speaking at his pre-match press conference on Wednesday, Leverkusen manager Bosz was inevitably faced with more questions regarding the future of Havertz, but said he has no doubts over either fielding the wantaway 21-year-old tomorrow night or where the latter's priorities lie.
"I will answer these questions [on Havertz] very shortly," he said.
"Yes, he will play and yes I'm convinced that he's 100 per cent still fighting for Leverkusen."