In the 84th minute of Bayer Leverkusen's 4-3 victory over Mainz, head coach Carles Martínez used his final two substitutions, bringing on Equi Fernández and Jonas Hofmann for Aleix García and Patrik Schick.
This meant Victor Boniface would once again be denied a chance to play. The Nigerian forward reacted by heading straight down the tunnel rather than returning to the bench, unlike Loïc Badé and Lucas Vázquez, who also remained unused substitutes.
Martínez addressed the situation in an interview with Kölner Stadt-Anzeiger after the game.
"I didn't notice it during the game. I don't know anything about it. If that's what happened, we'll speak to him," the Leverkusen coach said.
"I can understand that every player wants to help the team. At the same time, these decisions are part of football. At that moment, I decided to make those substitutions."
Leverkusen sporting managing director Simon Rolfes played down the incident, insisting it won't happen again.
"I don't know, maybe he needed to go to the toilet," he joked initially, before adding:
"Perhaps he went into the dressing room a little too early today. It won't happen next time."
Rolfes also sought to put Boniface's reaction into perspective, pointing to the striker's progress after struggling with recurring knee problems in recent years.
"Generally speaking, I'm very pleased with Boniface's development. Over the past few months, he's been getting fitter week by week. Of course, there's still room for improvement, and every player wants to play. However, he has behaved perfectly well overall and is a good member of the squad and the training group," Rolfes said.
"There are also other things the lads sometimes do that aren't always ideal. We want players who show emotion. You always have to consider whether it fits within the context of the team. I'm a fan of speaking to the lads first and telling them: 'That perhaps wasn't the smartest decision.' Then that's that."
Boniface has played just five minutes for Leverkusen this season. Following Christian Kofane's recent injury, Martínez suggested the Nigerian forward could get more playing time, but he will have to remain patient.
