Fairly significant A’s news today, as the team cuts its onetime first baseman Daric Barton, who’d appeared early in his career as if he’d be a team mainstay; and the A’s also let go of left-hander Travis Blackley, so valuable at times last year as an emergency starter and long man. Both were designated for assignment, and both can decline minor-league assignments if they clear waivers. Barton declined comment as he left the clubhouse. Blackley said, understandably, that his preference would be to pitch with a big-league team if he gets an opportunity. Blackley was very disappointed with the decision, but he said he isn’t angry; he said he knew it would be tough to make the team after poor results this spring. “You have to make a lot of money to get away with what I did during the spring and still make the team,” he said. He said he feels like “a piece of meat” this time of year because of the rough business nature of baseball, but he’s been through it before. Blackley had spent the offseason working out in preparation for this season, pumped up to be with a club where he finally felt as if he’d found a family.