McCarthy was dismissed on Monday after Wolves slipped into the bottom three of the Barclays Premier League following Sunday's 5-1 home defeat by West Brom.
However, when asked how much blame the players should take for Wolves' plight, Johnson told Sky Sports News: "All of it. The manager can maybe take five to 10% (of the blame). The rest of it is down to the lads. We have let Mick down, the club down and ourselves down."
Johnson, who was relegated with Birmingham last season before being signed by McCarthy in the summer and immediately being handed the captain's armband, believes Wolves have sufficient time to retrieve the current situation.
He said: "Thankfully we have got enough games to get enough points to get out out of trouble. We probably need six wins from 13 games and we have a good enough team to do that."
Club owner Steve Morgan is due back from a family holiday on Wednesday to step up the process of finding a replacement. Morgan and chief executive Jez Moxey are hoping to bring in McCarthy's successor before Wolves are next in action at Newcastle in 11 days time.
Former Charlton and West Ham boss Alan Curbishley continues to be the bookmakers' favourite after indicating he would be willing to talk to Morgan. Former Sunderland manager Steve Bruce and ex QPR boss Neil Warnock are also understood to be interested should Morgan get in touch.
But, if Wolves decide on an interim appointment until the end of the season, then Birmingham boss Chris Hughton could become a contender after reviving fortunes at St. Andrew's following relegation.
Moxey is adamant that Wolves had not started to look elsewhere for a potential manager until after McCarthy was informed of his fate at a training ground meeting yesterday morning.
He said: "I like to think that we are football professionals, so we understand what is happening in the market place, that we understand who is and who isn't around. It's part of our job. It's like a manager who has to scout players. But there wasn't any plot in the background."
Source: PA
Source: PA