Bayer Leverkusen have sacked head coach Peter Bosz and appointed former Stuttgart boss Hannes Wolf as his replacement until the end of this season.

A 4-0 win over Cologne in mid-December saw Leverkusen go top of the Bundesliga, but their form has collapsed since, with just four wins in their subsequent 18 matches in all competitions.

That prolonged slump has taken in a 6-3 aggregate defeat to Young Boys in the Europa League, which followed a humiliating exit from the DFB-Pokal at the hands of fourth-tier Rot-Weiss Essen in early February.

Following the 3-0 weekend defeat to Hertha Berlin, a result that left Leverkusen sixth in the table, Bosz expressed confidence that he would remain in his post.

However, the club's board had other ideas.

"In view of the development of football in recent weeks, we have come to the conclusion that the separation from Peter Bosz can no longer be avoided," said sporting director Rudi Voller in a statement. 

"The 3-0 defeat at Hertha on Sunday was unfortunately characteristic, our team has recently fallen into the same pattern over and over again. 

"We haven't been able to put an end to the repetitive mistakes and get back on the road to success. 

"After a factual and very open analysis of the sporting situation, we therefore agreed to make a change, despite the great appreciation for Peter Bosz."

Former Ajax head coach Bosz had done much to rehabilitate his reputation at Leverkusen having endured a nightmare half-season in charge of Borussia Dortmund in 2017-18.

A year later, in December 2018, he took over at the BayArena and inspired an upturn that resulted in Champions League qualification.

Leverkusen narrowly missed out on the top four last term, although they appeared to have put the loss of key man Kai Havertz to Chelsea behind them this time around before their post-Christmas disintegration.

Assistant coaches Hendrie Kruzen and Rob Maas and fitness coach Terry Peters have also been relieved of their duties, giving Wolf a surprise opportunity to prove himself again at Bundesliga level.

The 39-year-old was appointed Germany Under-18s coach after his dismissal by Belgian club Genk earlier this season.

Wolf amassed a 46 per cent win ratio when at Stuttgart between September 2016 and January 2018.

He then took charge of Hamburg during the 2018-19 season but was unable to lift the fallen giants out of 2. Bundesliga.

"I am very pleased with the trust that has been placed in me, because Bayer 04 is not just any club for me," Wolf said.

"Leverkusen has been one of the most attractive places in German football for many years. There is a highly ambitious environment here and a very talented, exciting team. 

"We all have opportunities to get into the European positions. It's up to us to get the maximum out of the remaining eight games."

Wolf will be assisted by veteran former Leverkusen player and coach Peter Hermann.