Raiders veteran OL Jackson Powers-Johnson leaves practice via injury

Jackson Powers-Johnson’s frustrating history with injuries resurfaced on Monday.The Raiders’ third-year interior offensive lineman left Monday morning’s practice with a trainer with approximately 45 minutes remaining in the workout and did not return.The nature and severity of the issue were not immediately known.But the sight of Powers-Johnson walking off the field served as an ominous reminder of the injury problems that have followed the former Oregon standout through his first two NFL seasons.Powers-Johnson has appeared in 23 games over his first two years with the Raiders, with injuries cutting short both seasons and preventing him from establishing the continuity the club hoped for when it drafted him.Those availability concerns, coupled with bouts of inconsistent play, have left Powers-Johnson fighting to retain his starting job at right guard this summer.He and second-year guard Caleb Rogers have been locked in a training-camp-long competition, with both players receiving extensive work with the starting offense.That makes the timing of Monday’s departure particularly concerning.The Raiders travel to Houston this week for a joint practice and preseason game against the Texans, whose formidable defensive front should provide one of the most revealing tests of the summer for Las Vegas’ offensive line.It remains unclear whether Powers-Johnson will make the trip....