Adeyemi has cut a frustrated figure in the past few weeks, prompting a public response from Kovac.
After a promising start to the season, the mercurial youngster has gone through a barren spell. He has failed to score or log an assist since late September.
During BVB's 1-0 victory over Köln last month, the winger threw a water bottle at the bench after he was subbed. Kovac publicly lambasted his star's behaviour.
The ex-Croatia and Bayern Munich manager said: "I think that's unnecessary. It's okay that he can be angry sometimes, but that's unnecessary, he's an adult."
Their relationship took another dramatic turn on the weekend during Dortmund's 1-1 draw with Hamburg. Kovac cut a frustrated figure on the sidelines, visibly remonstrating at Adeyemi after the winger made some poor decisions in the final third. The pair argued on the bench after Adeyemi's 66th minute substitution.
Looking for smarter football bets? Get expert previews, data-driven predictions & winning insights withGOAL Tips on Telegram. Join our growing community now!