And the boss expects Fletcher to be fit for the weekend clash at Tottenham.
Fletcher has been the subject of speculation linking him with a move away from Molineux after netting five times in his last six Premier League games.
But McCarthy is adamant the player is going nowhere and is confident he will have shaken off an ankle knock to face Spurs.
The Wolves boss said: "There is not a chance of Fletch leaving. If people call, I'd tell them no. He's too valuable for us.
"As regards his fitness, he's got a sore ankle. He rocked it in the FA Cup tie at Birmingham. He didn't train on Monday but he will be okay."
McCarthy is also hopeful that midfielder Dave Edwards (groin), newcomers Eggert Jonsson (groin) and skipper and defender Roger Johnson (ankle) will be fit for the trip to White Hart Lane.
Playmaker Jamie O'Hara could also come into contention to face his former club after a month on the side-lines since undergoing hernia surgery.
But full-back and knee injury victim Ronald Zubar is still "four or five weeks away from fitness", according to McCarthy.
McCarthy is hopeful veteran defender Jody Craddock can resume training later this week after five weeks out of action with a hamstring injury.
Craddock replaced Johnson in the side for the 2-1 home success over Sunderland in early December but suffered his setback during the latter stages of that game.
The 36-year-old, who has already indicated he will retire at the end of the season, then suffered a recurrence of the injury in training but is now close to fitness.
McCarthy said: "Hopefully this week Jody will train. He's been doing well with the physios but he hasn't been [training] with a ball yet.
"He did well when he came into the side and was unfortunate to get injured."
