If the club had signed one of the world's leading goalkeepers such as Gianluigi Buffon, he would have accepted the situation.
But both Howard and Roy Carroll, who was on the bench in Saturday's Premiership opener against Bolton, are inexperienced and Barthez is confident he will get his chance when the pressure games come in the Premiership and Champions League.
One problem for him, though, is that he is desperate to play in France's defence of their European Championship title next year in Portugal.
And he knows that France manager Jacques Santini cannot keep picking him if he is not playing first-team football.
"For the moment, it is not a problem," said Santini. "We will see what is happening at the beginning of September."
That is when the Euro 2004 qualifying programme resumes with games against Cyprus and Slovenia.
His demise has puzzled his old United teammate and former France captain Laurent Blanc who famously kissed Barthez's bald head before matches at the 1998 World Cup.
"He must have earned us 10 points at least last season," Blanc said. "He made some incredible saves in some vital matches."
