A week after he was designated for assignment by the Oakland Athletics, lefthander Travis Blackley will get to see his old teammates this weekend at Minute Maid Park. The Astros sent Class AAA outfielder Jake Goebbert to the A’s to acquire Blackley on Thursday. He’s expected to report to the Astros on Friday in time for the start of a three-game series between the defending American League West champion A’s and the Astros. “To have a guy who can stabilize our bullpen and be protection to our rotation was something we wanted to accomplish,” Astros general manager Jeff Luhnow said. Blackley, 30, split last season between the Giants and the A’s, combining to go 6-4 with a 4.10 ERA while helping Oakland win its division. “He had a terrific year last year and was a key part of that Oakland run,” said Luhnow, who has acquired four players from the Athletics since February. Luhnow also acquired left fielder/designated hitter Chris Carter, righthander Brad Peacock and minor league catcher Max Stassi in February in exchange for infielder Jed Lowrie and reliever Fernando Rodriguez.