Of the Philadelphia Flyers’ six goals in their three games against the Pittsburgh Penguins, three have come from defensemen and one has come from a rookie forward. Zero have come from three of their top-five goal scorers from the regular season — Claude Giroux, Jakub Voracek and Wayne Simmonds. In an effort to inject some life into his offense, head coach Dave Hakstol mixed up his lines during Tuesday’s practice, one day before Game 4 (Wednesday, 7 p.m. ET, NBCSN) with the Flyers trailing their first-round series 2-1.