The Spaniard refuses to divulge the details surrounding last week's incident.
The 42-year-old's future at The Riverside was called into question last Friday following a fiery team meeting which resulted in the Spanish manager storming out of the club's training ground.
Karanka was ordered to stay away for Saturday's defeat by Charlton Athletic, before the club insisted, as reported by HITC Sport, that he had not quit his role or been fired.
When asked to divulge the reasons behind the incident, the former Real Madrid assistant coach insisted that it was no longer relevant.
“The problem has not been a problem because I am here. It is better to speak about the future. I don’t think it is important to speak about what happened," he told a news conference, quoted by the Teesside Gazette. “The worst thing is we lost against Charlton on Sunday. We have to be full-on for Friday. The past is not important now.
“I said last week, and always, that the main thing is this club and the chairman. They are both going to be here after me. Always I will thank them for their support. The most important thing is that we win the game on Friday to show them.
“Friday is the best place to show everyone that we are a strong club, players, directors, fans technical staff, everyone. Let’s see and focus on that game.”
Karanka had a 20-minute clear-the-air meeting with chairman Steve Gibson on Teesside and everything appears to be okay for the moment.
However, their performance - and more importantly the result - against playoff rivals Hull City tomorrow night may well illustrate whether the players are behind their manager or not.