Mangum is out of the lineup for Sunday's game against the Angels.
Mangum will be riding pine for the series finale after he started in each of the Pirates' previous four games while going 3-for-12 with a double, a walk, two runs and two RBI during that stretch. The 30-year-old outfielder has noticed only a slight downturn in playing time since Oneil Cruz returned from the injured list Aug. 18, but Mangum could see his opportunities dwindle a bit more when Ryan O'Hearn (quadriceps) likely come back from the IL during the upcoming week.