The 17-year-old, who signed his first professional contract with the Cottagers earlier this year, made his senior debut as a substitute in last weekend's 5-0 defeat at Manchester City.
"We have a very good youth academy here at Fulham so it is the right way to bring the young players into the Premier League," Magath told the club's official website.
"Pat is a very big talent and he will have a great career in front of him, so I think it is good for him to make the experience now in the Premier League, so he will get used to it.
"He will be a player that we need in the future."
Roberts has reportedly been watched by La Liga duo Real Madrid and Barcelona.