WASHINGTON, April 6 (Xinhua) -- Both McGrady and Yao Ming sat out the Rockets' National Basketball Association contest against the Portland Trail Blazers on Friday due to back problems.

    McGrady's absence comes just two days after the swingman managed to play just six minutes in the first quarter of Wednesday's 110-99 loss to Golden State with a stiff lower back.

    Yao, who is listed as day-to-day with a sore lower back, is unaware of how he suffered his injury after scoring nine points and grabbing 11 rebounds in 30 minutes against the Warriors.