Rooney missed from 12 yards against Bolton last weekend while he also had a penalty saved by Costel Pantilimon in United's victory over rivals Manchester City in the FA Cup a fortnight ago.
The England striker has now missed four of his last eight attempts from the spot.
However, Ferguson is happy for Rooney to continue to take responsibility from 12 yards.
"If he is happy to take them, I am happy to suffer," he said.
Rooney meanwhile has rubbished the talk and told MUTV: "Of course I'll still take the penalties. These things happen - sometimes you miss.
"It's not nice to miss but I'm not worried about it."
The Red Devils face Arsenal at the Emirates Stadium this afternoon.