Derek Holland's knee surgery last week involved a microfracture procedure to repair the cartilage behind his left kneecap. The fact that it was a microfracture procedure is one reason the club has put a midseason timeline on Holland's return, rather than sooner. The procedure is designed to stimulate blood flow and help it heal. Holland said Saturday he hurt his knee when his dog, Wrigley, ran up the stairs and tripped him. The left-hander's knee slammed the stair, causing the injury. Read more http://espn.go.com/dallas/mlb/story...underwent-microfracture-procedure-repair-knee
