SEATTLE - Even scouts at Tuesday’s game couldn’t agree about Ryan Madson’s pitch selection to Leonys Martin in the ninth inning. Martin hit a two-out walkoff homer on a 1-2 changeup from Madson, the fourth changeup of the at-bat. “He needed to throw him a fastball up in the zone there,” one scout said. [...] Madson’s changeup is one of the better ones in baseball, and he and manager Bob Melvin both said it was a matter of execution, not the selection. “If he hits the catcher’s glove, he gets a swing-and-miss,” one scout agreed. “You can throw 10 in a row if you put them in the right spot,” Madson said. If I throw a fastball there and he hits one out, everyone says, ‘You’d thrown him three changeups and he swung and missed two of them! Why’d you throw him a fastball?’ Madson said with a chuckle. First baseman-outfielder Mark Canha had season-ending surgery to repair his left hip Tuesday in Vail, Colo.; specialist Dr.