Rooney has just one United goal to his name this season - a penalty against West Ham - and was left out of their last Premier League game at Everton after lurid allegations about his private life surfaced in the press.
The 24-year-old was restored to the starting line-up on Tuesday night but failed to find the net as Rangers held United to a scoreless draw at Old Trafford. But Fletcher says it is only a matter of time before Rooney gets back on the goal trail.
"There is nothing to worry about with Wayne," said Fletcher. "Wayne is a top player and the goals will come because he has so much quality. It is up to us create the chances for him and give him the opportunities to score.
"Maybe we have not done that lately. Against Rangers we didn't create anything for him. He will be frustrated with that but it will come."
Fletcher also defender Sir Alex Ferguson's decision to make ten changes to the United team that drew 3-3 with Everton at Goodison Park.
"We have a big squad and everyone has a lot of ability," he said. "It is difficult for the players coming in because they don't have that match sharpness. But training is intense and everyone is good enough to play in this team. The manager felt things needed freshening up and the team was good enough to win the match. I agree.
"What happened last night was that we came up against a team with five defenders and three centre-halves. Usually when you are up against teams who get men behind the ball, they have the extra man in midfield. It proved difficult to break down."