PHOENIX -- Just five days after undergoing surgery to repair a torn meniscus in his right knee, closer Grant Balfour was back on the field playing catch. The A's closer threw from flat ground to River Cats pitching coach Rick Rodriguez.

Balfour completed each throw without issue. With each toss you could hear the ball cutting through the air and the glove popping. After the session Balfour told the trainers that he didn't feel any pain in the knee. He then walked back to the clubhouse for more conditioning.

Throwing never bothered Balfour's injured knee in the first place. He only felt pain when running and cutting as he tried to field baseballs.

He is expected to be out 4-6 weeks from the day of his Feb. 14 surgery. Based on his progress thus far, it appears he could realistically return in time for Opening Day on April 1 against the Mariners in Oakland.