Tevez, who has frequently agitated for a move away from Eastlands, ended up staying with the club this summer when no suitable buyers came forward and he has been out of the first team since the start of the current campaign, with the likes of Edin Dzeko, Sergio Aguero and Mario Balotelli all ahead of him.
He was again on the bench for the trip to Germany and Mancini has said he declined to go on the pitch when asked.
Tevez's actions drew a scathing response from the television pundits, with Souness reacting furiously.
"He (Tevez) is one bad apple," he told Sky Sports 2.
"He can undo all the good work that has been done (at City). He's a disgrace to football. He epitomises what most people think is wrong with modern football.
"It is totally unacceptable. He's a football player and he is paid to play.
"He is refusing to help his team-mates. It's all about him, him, him."
Souness also suggested the Argentina forward's attitude may have contributed to his exit from Manchester United, where he played prior to his Eastlands switch.
"Why didn't Fergie take him? Fergie (Sir Alex Ferguson) is the oldest fox in the business and he must have seen something he didn't like in him," said the Scot.
Mancini is now keen to see the back of Tevez once and for all and Souness believes that is the right move for City, who he thinks could risk losing their manager if they fail to agree.
"He (Mancini) walked into a hornet's nest with him (Tevez) and several other players who were at the club at the time," continued Souness.
"That would cause you to walk away from the job. How can you deal with players acting like that?"
Mark Hughes was City manager when Tevez moved to Eastlands and believes the player's personal situation is at the root of the issue.
"The problem with Carlos is he missed his family," said Hughes on Sky Sports 2.
"That's why he said if it was possible he wanted to leave the club, he had this situation with his family.
"There is obviously no relationship whatsoever, or you would imagine given the events of this evening, with the manager. That needs to be mended and if it can't then something else has to happen."
Former United striker Dwight Yorke also believes Mancini has some work on his hands resolving an awkward situation with a player who is lavishly paid at City and would be affordable to only a small number of top clubs.
"I don't condone what he's done, in terms of refusing to go on the pitch. No-one likes to see that," said Yorke.
"We don't know the ins and outs but they need to sort that out.
You don't need that around the place.
"The manager has got some work to do and he alone can make those decisions."
Former Bayern Munich and Germany midfielder Stefan Effenberg, who captained Bayern to their last Champions League triumph in 2001, said the Argentina forward's behaviour was unacceptable and that he, like Mancini, would never consider the player again.
"That player would never play in the same club as me again - that goes without saying," he told Germany's Sky television, for whom he now works as a pundit.
"There is a clear order from the coach and he disregards it.
"That is poor behaviour and the club has got to come down hard on it."
According to Effenberg, Tevez will also now have problems finding another employer who would still be keen on him after the incident in last night's 2-0 loss to Bayern.
"Other clubs are going to have to consider whether they want to sign a player with such a character," he added.
"You just don't do something like that. It is disrespectful to your team-mates and is not just in spite of the coach, but in spite of the whole team.
"I hope that they actually go through with what Mancini says and that he never plays for the club again."Stoke City boss Tony Pulis, speaking ahead of his side's Europa League tie with Besiktas, said of the Tevez incident: "Players get disappointed and players have got egos, but you deal with it.
"I'm sure they will deal with it in the right and proper manner.
"What is said and done between two people is said and done, so they have to react and do what they have to do at Man City."