Hughton was replaced by youth coach Neil Adams following last weekend's 1-0 home defeat to fellow strugglers West Brom.
That loss left 17th-placed Norwich just five points above Fulham, who are third-bottom after a crucial 2-1 victory at Aston Villa.
Fulham can cut that gap to two points with a home victory over Adams' team on Saturday, but Magath - who replaced Rene Meulensteen at Craven Cottage in February - believes the managerial change will make Norwich more dangerous opposition.
"For us it doesn't matter who we play but Norwich have a very bad schedule. They have very, very difficult games," the German said.
"They changed manager now and that will give them new energy so we have to be careful. They will fight for 90 minutes and it will not be an easy game for us."
Magath thinks Norwich made the right move by appointing their new boss from within, but suggested the switch may not be enough to save their Premier League status.
"I think it was a very good decision for them but maybe it is too late," he added.
"Now as a manager you can't do a lot of things. It is only a question of the atmosphere - not of training sessions or tactics.
"I think he has a chance - the new man coming from the youth team - has a chance of getting a response from the team."
