Mariners ace Bryan Woo injures pectoral muscle in win

(Photo credit: Erik Williams-Imagn Images)

Seattle ace Bryan Woo left his start in the Mariners' 4-0 road win over the Houston Astros on Friday night due to tightness in a pectoral muscle.

After holding the Astros to one hit over five innings, the right-hander was on the mound warming up for the sixth when, after a throw, he looked down at his glove and appeared to show frustration. Manager Dan Wilson and t