Photo by ameschen.Ken Rosenthal at FOXsports.com had the scoop that beleaguered Nationals manager Manny Acta will be relieved of his duties at some point this week, replaced by current bench coach and former major league manager Jim Riggleman. The forty-year-old Acta, the youngest active manager in the bigs when he was hired in 2007, has accumulated a 148-235 record in his two-plus seasons with the team — but has seen a steady negative decline…