Oakland Athletics Closer Grant Balfour Will require arthroscopic right knee surgery Thursday and is expected to miss four to six weeks. Balfour Said he feels good about the surgery and believes he will be back by April 1st opening day. The Oakland A's are hopeful that the Hard Throwing 35 year old Australian will be ready to go opening day. The A's exercised their $4.5 million option to keep Balfour through this season. Balfour was diagnosed with a torn meniscus following an MRI and will undergo the surgery this afternoon. Balfour went 3-2 with a 2.53 ERA and 24 saves last season for the AL West champions. A's fans are hopeful there closer stays healthy and continues his Raging ways.