The Minnesota Twins have placed left-hander Scott Diamond on waivers, a person with direct knowledge said Wednesday afternoon. Diamond, 27, lost out to right-hander Kyle Gibson in his bid to claim the final spot in the Twins’ starting rotation. Like right-hander Vance Worley, who cleared waivers last week and was sold Tuesday to the Pittsburgh Pirates, Diamond is out of options and must clear waivers in order to be sent to the minor leagues. Waivers were requested on Diamond Tuesday, the source said, which means his waiver period expires at 1 p.m. Central on Thursday. Any team claiming Diamond must keep him on its big-league roster or subject him to the same waiver process the Twins have entered. Opening Day rosters must be set Sunday by 2 p.m. CDT. The Toronto Blue Jays, Philadelphia Phillies, San Diego Padres and Washington Nationals are among teams in need of help at the back of their big-league rotations. Diamond is from Guelph, Ontario, a Toronto suburb. Acquired from the Atlanta Braves in the Rule 5 draft after the 2010 season, Diamond struggled as a rookie in 2011 but rebounded to go 12-9 with a 3.54 earned run average in 27 starts in 2012.