His absence is, undoubtedly, unfortunately timed, with Liverpool on the verge of reaching the Champions League final as they lead Roma 5-2 after a fine first home leg performance.
It was reported on Friday morning that Buvac had left Liverpool, although the Reds quickly clarified to BBC Sport that he was still employed by the club and was only on leave until the end of the season.
In October 2015, he joined Liverpool manager Jurgen Klopp at Anfield as he took up the role of assistant manager at the Premier League club. They say he remains a club employee, but the timing is extraordinary.
Anfield observers had noticed that Buvac and Klopp, who used to be inseparable, have not interacted during games as they had done before, particularly in terms of talking. "Short-term effect is negligible but Klopp will want somebody else to bounce ideas off next season if he doesn't come back".More news: Here's Where Prince Louis Stands In The Royal Family!
In 2013, Nuri Sahin claimed that Buvac was "basically Klopp's twin" with both seeing football "in exactly the same way".
According to the Mirror, Zeljko Buvac has quit the club just two days away from the all important semi final. He will also be a steadying presence at the side of the German coach.
The pair have labored collectively ever since, at Borussia Dortmund and till now Liverpool, with Buvac typically thought to be "the mind" who has helped develop the high-speed attacking model that has develop into Klopp's signature.