By Daniel Chavkin The pitcher was diagnosed with non-Hodgkin lymphoma in April. Phillies minor league pitcher Corey Phelan has died at the age of 20 after dealing with cancer, the team announced in a statement Thursday. “Corey’s positive presence and selflessness influenced everyone around him,” the team said in the statement. “While he was incredibly passionate about the game of baseball, his love for his family and his strong faith superseded everything else.” Along with the team’s statement, Phillies director of player development Preston Mattingly mourned Phelan’s loss. “Corey is and will …